Phenytoin Injection

Phenytoin injection is used to treat primary generalized tonic-clonic seizures (formerly known as a grand mal seizure; seizure that involves the entire body) and to treat and prevent seizures that may begin during or after surgery to the brain or nervous system. Phenytoin injection may also be used to control certain types of seizures in people who cannot take oral phenytoin. Phenytoin is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.

Phenytoin injection comes as a solution (liquid) to be slowly injected intravenously (into a vein) by a doctor or nurse in a medical facility. It is usually injected once every 6 or 8 hours.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Phenytoin injection is also used to control irregular heartbeat. Talk to your doctor about the risks of using this medication for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before receiving phenytoin injection,

• tell your doctor and pharmacist if you are allergic to phenytoin, other hydantoin medications such as ethotoin (Peganone) or fosphenytoin (Cerebyx), any other medications, or any of the ingredients in phenytoin injection. Ask your pharmacist for a list of the ingredients.

• tell your doctor if you are taking delavirdine (Rescriptor). Your doctor will probably not want you to receive phenytoin injection if you are taking this medication.

• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: albendazole (Albenza); amiodarone (Nexterone, Pacerone); anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); antifungal medications such as fluconazole (Diflucan), ketoconazole (Nizoral), itraconazole (Onmel, Sporanox, Tolsura), miconazole (Oravig), posaconazole (Noxafil), and voriconazole (Vfend); certain antivirals such as efavirenz (Sustiva, in Atripla), indinavir (Crixivan), lopinavir (in Kaletra), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Invirase); bleomycin; capecitabine (Xeloda); carboplatin; chloramphenicol; chlordiazepoxide (Librium, in Librax); cholesterol medications such as atorvastatin (Lipitor, in Caduet), fluvastatin (Lescol), and simvastatin (Zocor, in Vytorin); cisplatin; clozapine (Fazaclo, Versacloz); cyclosporine (Gengraf, Neoral, Sandimmune); diazepam (Valium); diazoxide (Proglycem); digoxin (Lanoxin); disopyramide (Norpace); disulfiram (Antabuse); doxorubicin (Doxil); doxycycline (Acticlate, Doryx, Monodox, Oracea, Vibramycin); fluorouracil; fluoxetine (Prozac, Sarafem, in Symbyax, others); fluvoxamine (Luvox); folic acid; fosamprenavir (Lexiva); furosemide (Lasix); H₂ antagonists such as cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid), and ranitidine (Zantac); hormonal contraceptives (birth control pills, patches, rings, or injections); hormone replacement therapy (HRT); irinotecan (Camptosar); isoniazid (Laniazid, in Rifamate, in Rifater); medications for mental illness and nausea; other medications for seizures such as carbamazepine (Carbatrol, Equetro, Tegretol, others), ethosuximide (Zarontin), felbamate (Felbatol), lamotrigine (Lamictal), methsuximide (Celontin), oxcarbazepine (Trilepta, Oxtellar XR), phenobarbital, topiramate (Topamax), and valproic acid (Depakene); methadone (Dolophine, Methadose); methotrexate (Otrexup, Rasuvo, Trexall, Xatmep); methylphenidate (Daytrana, Concerta, Metadate, Ritalin); mexiletine; nifedipine (Adalat, Procardia), nimodipine (Nymalize), nisoldipine (Sular); omeprazole (Prilosec); oral steroids such as dexamethasone, methylprednisolone (Medrol), prednisolone, and prednisone (Rayos); paclitaxel (Abraxane, Taxol); paroxetine (Paxil, Pexeva); praziquantel (Biltricide); quetiapine (Seroquel); quinidine (in Nuedexta); reserpine; rifampin (Rifadin, Rimactane, in Rifamate, in Rifater); salicylate pain relievers such as aspirin, choline magnesium trisalicylate, choline salicylate, diflunisal, magnesium salicylate (Doan's, others), and salsalate; sertraline (Zoloft); sulfa antibiotics; teniposide; theophylline (Elixophyllin, Theo-24, Theochron); ticlopidine; tolbutamide; trazodone; verapamil (Calan, Verelan, in Tarka); vigabatrin (Sabril); and vitamin D. Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.

• tell your doctor what herbal products you are taking, especially St. John's wort.

• tell your doctor if you have ever developed a liver problem while taking phenytoin. Your doctor will probably not want you to receive phenytoin injection.

• tell your doctor if you drink or have ever drunk large amounts of alcohol. Tell your doctor if you have had laboratory testing that reported you have an inherited risk factor that makes it more likely that you could have an serious skin reaction to phenytoin. Also, tell your doctor if you have or have ever had diabetes, porphyria (condition in which certain natural substances build up in the body and may cause stomach pain, changes in thinking or behavior, or other symptoms), low levels of albumin in your blood, or kidney or liver disease.

• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. You should not become pregnant while you are receiving phenytoin. Talk to your doctor about effective birth control methods that you can use during your treatment. If you become pregnant while receiving phenytoin, call your doctor. Phenytoin may harm the fetus.

• if you are having surgery, including dental surgery, tell the doctor or dentist that you are receiving phenytoin.

• you should know that this medication may cause dizziness, drowsiness, and problems with coordination. Do not drive a car or operate machinery until you know how this medication affects you.

• talk to your doctor about the safe use of alcohol while you are taking this medication.

• talk to your doctor about the best way to care for your teeth, gums, and mouth during your treatment with phenytoin. It is very important that you care for your mouth properly to decrease the risk of gum damage caused by phenytoin.

Phenytoin may cause an increase in your blood sugar. Talk to your doctor about the symptoms of high blood sugar and what to do if you experience these symptoms.

• Phenytoin injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • difficulty falling asleep or staying asleep

  • uncontrollable eye movements

  • abnormal body movements

  • loss of coordination

  • confusion

  • slurred speech

  • headache

  • changes in your sense of taste

  • constipation

  • unwanted hair growth

  • coarsening of facial features

  • enlargement of lips

  • overgrowth of gums

  • pain or curving of the penis

• Some side effects can be serious. If you experience any of the following symptoms or those listed in the SPECIAL PRECAUTIONS section, call your doctor immediately:

  • swelling, discoloration, or pain at the injection site

  • rash

  • hives

  • itching

  • swelling of the eyes, face, throat, tongue, arms, hands, ankles, or lower legs

  • difficulty breathing or swallowing

  • hoarseness

  • swollen glands

  • nausea

  • vomiting

  • yellowing of the skin or eyes

  • pain in upper right part of the stomach

  • excessive tiredness

  • unusual bruising or bleeding

  • small red or purple spots on skin

  • loss of appetite

  • flu-like symptoms

  • fever, sore throat, rash, mouth ulcers, or easy bruising, or facial swelling

• Phenytoin injection may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.

• If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

• Taking phenytoin may increase the risk that you will develop problems with your lymph nodes including Hodgkin's disease (cancer that begins in the lymph system). Talk to your doctor about the risks of using this medication to treat your condition.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• uncontrollable eye movements

• loss of coordination

• slow or slurred speech

• fatigue

• blurred vision

• uncontrollable shaking of a part of the body

• nausea

• vomiting

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your response to phenytoin injection.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are receiving phenytoin injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Drug	Interaction
Repaglinide	Repaglinide The metabolism of Repaglinide can be decreased when combined with Phenytoin.
Montelukast	Montelukast The metabolism of Phenytoin can be decreased when combined with Montelukast.
Leflunomide	Leflunomide The metabolism of Phenytoin can be decreased when combined with Leflunomide.
Delavirdine	Delavirdine The serum concentration of Delavirdine can be decreased when it is combined with Phenytoin.
Nevirapine	Nevirapine The metabolism of Nevirapine can be decreased when combined with Phenytoin.
Atorvastatin	Atorvastatin The serum concentration of Atorvastatin can be decreased when it is combined with Phenytoin.
Dolasetron	Dolasetron The risk or severity of adverse effects can be increased when Phenytoin is combined with Dolasetron.
Alendronate	Alendronate The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Alendronic acid.
Aminophylline	Aminophylline The metabolism of Aminophylline can be increased when combined with Phenytoin.
Candesartan	Candesartan The metabolism of Phenytoin can be decreased when combined with Candesartan.
Cilostazol	Cilostazol The metabolism of Cilostazol can be increased when combined with Phenytoin.
Clopidogrel	Clopidogrel The metabolism of Clopidogrel can be decreased when combined with Phenytoin.
Diphenoxylate	Diphenoxylate The risk or severity of adverse effects can be increased when Phenytoin is combined with Diphenoxylate.
Erythromycin and Sulfisoxazole	Erythromycin and Sulfisoxazole The metabolism of Phenytoin can be decreased when combined with Erythromycin.
Estrogen and Progestin (Oral Contraceptives)	Estrogen and Progestin (Oral Contraceptives) The therapeutic efficacy of Phenytoin can be decreased when used in combination with Conjugated estrogens.
Fenofibrate	Fenofibrate The metabolism of Fenofibrate can be increased when combined with Phenytoin.
Guanfacine	Guanfacine The metabolism of Guanfacine can be increased when combined with Phenytoin.
Magnesium Gluconate	Magnesium Gluconate Magnesium gluconate can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Magnesium Hydroxide	Magnesium Hydroxide Magnesium hydroxide can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Magnesium Oxide	Magnesium Oxide Magnesium oxide can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Mycophenolate	Mycophenolate The metabolism of Mycophenolic acid can be increased when combined with Phenytoin.
Nafarelin	Nafarelin The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Nafarelin.
Naratriptan	Naratriptan The risk or severity of adverse effects can be increased when Phenytoin is combined with Naratriptan.
Olsalazine	Olsalazine The serum concentration of Phenytoin can be increased when it is combined with Olsalazine.
Paregoric	Paregoric The metabolism of Phenytoin can be decreased when combined with Morphine.
Penbutolol	Penbutolol The metabolism of Phenytoin can be decreased when combined with Acebutolol.
Pentazocine	Pentazocine The risk or severity of adverse effects can be increased when Phenytoin is combined with Pentazocine.
Prednisone	Prednisone The serum concentration of Phenytoin can be decreased when it is combined with Prednisone.
Ranitidine	Ranitidine The metabolism of Phenytoin can be decreased when combined with Ranitidine.
Reserpine	Reserpine The serum concentration of Phenytoin can be decreased when it is combined with Reserpine.
Rizatriptan	Rizatriptan The risk or severity of adverse effects can be increased when Phenytoin is combined with Rizatriptan.
Sumatriptan	Sumatriptan The risk or severity of adverse effects can be increased when Phenytoin is combined with Sumatriptan.
Tacrolimus	Tacrolimus The serum concentration of Tacrolimus can be decreased when it is combined with Phenytoin.
Tizanidine	Tizanidine The risk or severity of adverse effects can be increased when Phenytoin is combined with Tizanidine.
Triamcinolone	Triamcinolone The serum concentration of Triamcinolone can be decreased when it is combined with Phenytoin.
Zolmitriptan	Zolmitriptan The risk or severity of adverse effects can be increased when Phenytoin is combined with Zolmitriptan.
Doxycycline Injection	Doxycycline Injection The serum concentration of Doxycycline can be decreased when it is combined with Phenytoin.
Fluconazole Injection	Fluconazole Injection The serum concentration of Phenytoin can be increased when it is combined with Fluconazole.
Hydromorphone Injection	Hydromorphone Injection The metabolism of Hydromorphone can be decreased when combined with Phenytoin.
Meperidine Injection	Meperidine Injection The serum concentration of Meperidine can be decreased when it is combined with Phenytoin.
Methylprednisolone Injection	Methylprednisolone Injection The serum concentration of Phenytoin can be decreased when it is combined with Methylprednisolone.
Metoclopramide Injection	Metoclopramide Injection The risk or severity of sedation can be increased when Phenytoin is combined with Metoclopramide.
Metronidazole Injection	Metronidazole Injection The serum concentration of Metronidazole can be decreased when it is combined with Phenytoin.
Morphine Injection	Morphine Injection The metabolism of Phenytoin can be decreased when combined with Morphine.
Pamidronate Injection	Pamidronate Injection The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Pamidronic acid.
Zidovudine Injection	Zidovudine Injection The metabolism of Zidovudine can be decreased when combined with Phenytoin.
Altretamine	Altretamine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Amphetamine.
Cyclosporine	Cyclosporine The serum concentration of Cyclosporine can be decreased when it is combined with Phenytoin.
Ondansetron	Ondansetron The metabolism of Ondansetron can be decreased when combined with Phenytoin.
Granisetron	Granisetron The risk or severity of adverse effects can be increased when Phenytoin is combined with Granisetron.
Torsemide	Torsemide The metabolism of Phenytoin can be decreased when combined with Torasemide.
Olanzapine	Olanzapine The metabolism of Phenytoin can be decreased when combined with Olanzapine.
Alosetron	Alosetron The metabolism of Alosetron can be decreased when combined with Phenytoin.
Dofetilide	Dofetilide The metabolism of Dofetilide can be increased when combined with Phenytoin.
Entacapone	Entacapone The metabolism of Entacapone can be decreased when combined with Phenytoin.
Eprosartan	Eprosartan The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Eprosartan.
Hydroxychloroquine	Hydroxychloroquine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Hydroxychloroquine.
Meloxicam	Meloxicam The serum concentration of Meloxicam can be increased when it is combined with Phenytoin.
Orlistat	Orlistat Orlistat can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Oxcarbazepine	Oxcarbazepine The serum concentration of Phenytoin can be increased when it is combined with Oxcarbazepine.
Pantoprazole	Pantoprazole The metabolism of Phenytoin can be decreased when combined with Pantoprazole.
Risedronate	Risedronate The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Risedronic acid.
Sevelamer	Sevelamer Sevelamer can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Telmisartan	Telmisartan The metabolism of Phenytoin can be decreased when combined with Telmisartan.
Zaleplon	Zaleplon The metabolism of Zaleplon can be increased when combined with Phenytoin.
Anakinra	Anakinra The metabolism of Phenytoin can be increased when combined with Anakinra.
Desloratadine	Desloratadine The risk or severity of adverse effects can be increased when Phenytoin is combined with Desloratadine.
Linezolid	Linezolid The risk or severity of adverse effects can be increased when Phenytoin is combined with Linezolid.
Trimipramine	Trimipramine The metabolism of Phenytoin can be decreased when combined with Trimipramine.
Etanercept Injection	Etanercept Injection The metabolism of Phenytoin can be increased when combined with Etanercept.
Glycopyrrolate	Glycopyrrolate Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Glycopyrronium.
Modafinil	Modafinil The metabolism of Phenytoin can be decreased when combined with Modafinil.
Tenofovir	Tenofovir The metabolism of Tenofovir can be increased when combined with Phenytoin.
Choline Magnesium Trisalicylate	Choline Magnesium Trisalicylate The serum concentration of Phenytoin can be increased when it is combined with Choline magnesium trisalicylate.
Sirolimus	Sirolimus The metabolism of Sirolimus can be increased when combined with Phenytoin.
Dutasteride	Dutasteride The metabolism of Dutasteride can be increased when combined with Phenytoin.
Epinephrine Injection	Epinephrine Injection The metabolism of Phenytoin can be decreased when combined with Epinephrine.
Eplerenone	Eplerenone The metabolism of Eplerenone can be increased when combined with Phenytoin.
Escitalopram	Escitalopram The serum concentration of Escitalopram can be increased when it is combined with Phenytoin.
Zonisamide	Zonisamide Phenytoin may increase the excretion rate of Zonisamide which could result in a lower serum level and potentially a reduction in efficacy.
Adalimumab Injection	Adalimumab Injection The metabolism of Phenytoin can be increased when combined with Adalimumab.
Aripiprazole	Aripiprazole The metabolism of Aripiprazole can be increased when combined with Phenytoin.
Atomoxetine	Atomoxetine The risk or severity of adverse effects can be increased when Phenytoin is combined with Atomoxetine.
Dexmethylphenidate	Dexmethylphenidate The serum concentration of Phenytoin can be increased when it is combined with Dexmethylphenidate.
Ezetimibe	Ezetimibe The metabolism of Ezetimibe can be increased when combined with Phenytoin.
Atazanavir	Atazanavir The metabolism of Atazanavir can be increased when combined with Phenytoin.
Almotriptan	Almotriptan The metabolism of Almotriptan can be decreased when combined with Phenytoin.
Eletriptan	Eletriptan The metabolism of Eletriptan can be decreased when combined with Phenytoin.
Mefloquine	Mefloquine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Mefloquine.
Rosuvastatin	Rosuvastatin The metabolism of Rosuvastatin can be increased when combined with Phenytoin.
Vardenafil	Vardenafil The metabolism of Vardenafil can be increased when combined with Phenytoin.
Aprepitant	Aprepitant The metabolism of Aprepitant can be decreased when combined with Phenytoin.
Memantine	Memantine The metabolism of Phenytoin can be decreased when combined with Memantine.
Tegaserod	Tegaserod The metabolism of Phenytoin can be decreased when combined with Tegaserod.
Tadalafil	Tadalafil The metabolism of Tadalafil can be increased when combined with Phenytoin.
Fosamprenavir	Fosamprenavir The serum concentration of Phenytoin can be decreased when it is combined with Fosamprenavir.
Frovatriptan	Frovatriptan The risk or severity of adverse effects can be increased when Phenytoin is combined with Frovatriptan.
Progesterone	Progesterone The metabolism of Phenytoin can be increased when combined with Progesterone.
Apomorphine Injection	Apomorphine Injection The metabolism of Apomorphine can be decreased when combined with Phenytoin.
Infliximab Injection	Infliximab Injection The metabolism of Phenytoin can be increased when combined with Infliximab.
Oxandrolone	Oxandrolone The metabolism of Phenytoin can be decreased when combined with Oxandrolone.
Protriptyline	Protriptyline The risk or severity of adverse effects can be increased when Phenytoin is combined with Protriptyline.
Rifaximin	Rifaximin The metabolism of Phenytoin can be increased when combined with Rifaximin.
Duloxetine	Duloxetine The metabolism of Duloxetine can be increased when combined with Phenytoin.
Norethindrone	Norethindrone The metabolism of Norethisterone can be increased when combined with Phenytoin.
Trospium	Trospium Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Trospium.
Bosentan	Bosentan The metabolism of Bosentan can be decreased when combined with Phenytoin.
Cinacalcet	Cinacalcet The metabolism of Phenytoin can be decreased when combined with Cinacalcet.
Erlotinib	Erlotinib The metabolism of Erlotinib can be increased when combined with Phenytoin.
Eszopiclone	Eszopiclone The risk or severity of CNS depression can be increased when Phenytoin is combined with Eszopiclone.
Ganciclovir	Ganciclovir The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Ganciclovir.
Solifenacin	Solifenacin Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Solifenacin.
Valganciclovir	Valganciclovir The therapeutic efficacy of Phenytoin can be decreased when used in combination with Valganciclovir.
Voriconazole	Voriconazole The serum concentration of Phenytoin can be decreased when it is combined with Voriconazole.
Dextroamphetamine	Dextroamphetamine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Amphetamine.
Peginterferon Alfa-2b (PEG-Intron)	Peginterferon Alfa-2b (PEG-Intron) The metabolism of Phenytoin can be increased when combined with Peginterferon alfa-2b.
Sodium Oxybate	Sodium Oxybate Sodium oxybate may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Ibandronate	Ibandronate The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Ibandronate.
Isocarboxazid	Isocarboxazid The risk or severity of adverse effects can be increased when Phenytoin is combined with Isocarboxazid.
Ramelteon	Ramelteon The metabolism of Ramelteon can be decreased when combined with Phenytoin.
Darifenacin	Darifenacin The metabolism of Darifenacin can be decreased when combined with Phenytoin.
Fentanyl	Fentanyl The risk or severity of adverse effects can be increased when Phenytoin is combined with Fentanyl.
Deferasirox	Deferasirox The serum concentration of Deferasirox can be decreased when it is combined with Phenytoin.
Tipranavir	Tipranavir The serum concentration of Tipranavir can be decreased when it is combined with Phenytoin.
Felbamate	Felbamate The serum concentration of Phenytoin can be increased when it is combined with Felbamate.
Ranolazine	Ranolazine The metabolism of Phenytoin can be increased when combined with Ranolazine.
Abatacept Injection	Abatacept Injection The metabolism of Phenytoin can be increased when combined with Abatacept.
Rasagiline	Rasagiline The risk or severity of adverse effects can be increased when Phenytoin is combined with Rasagiline.
Imatinib	Imatinib The metabolism of Imatinib can be increased when combined with Phenytoin.
Sitagliptin	Sitagliptin The metabolism of Phenytoin can be decreased when combined with Sitagliptin.
Gefitinib	Gefitinib The metabolism of Gefitinib can be increased when combined with Phenytoin.
Paliperidone	Paliperidone The risk or severity of adverse effects can be increased when Phenytoin is combined with Paliperidone.
Exemestane	Exemestane The metabolism of Exemestane can be increased when combined with Phenytoin.
Bortezomib	Bortezomib The metabolism of Bortezomib can be increased when combined with Phenytoin.
Fulvestrant Injection	Fulvestrant Injection The metabolism of Fulvestrant can be increased when combined with Phenytoin.
Oxaliplatin Injection	Oxaliplatin Injection Oxaliplatin can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Posaconazole	Posaconazole The serum concentration of Phenytoin can be decreased when it is combined with Posaconazole.
Primaquine	Primaquine The metabolism of Phenytoin can be decreased when combined with Primaquine.
Bismuth Subsalicylate	Bismuth Subsalicylate The protein binding of Phenytoin can be decreased when combined with Bismuth subsalicylate.
Darunavir	Darunavir The serum concentration of Phenytoin can be decreased when it is combined with Darunavir.
Dimenhydrinate	Dimenhydrinate The risk or severity of adverse effects can be increased when Phenytoin is combined with Dimenhydrinate.
Lisdexamfetamine	Lisdexamfetamine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Lisdexamfetamine.
Nabilone	Nabilone Nabilone may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Retapamulin	Retapamulin The metabolism of Retapamulin can be increased when combined with Phenytoin.
Sorafenib	Sorafenib The metabolism of Phenytoin can be decreased when combined with Sorafenib.
Sunitinib	Sunitinib The metabolism of Sunitinib can be increased when combined with Phenytoin.
Dronabinol	Dronabinol Dronabinol may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Lapatinib	Lapatinib The metabolism of Lapatinib can be increased when combined with Phenytoin.
Levocetirizine	Levocetirizine The risk or severity of adverse effects can be increased when Phenytoin is combined with Levocetirizine.
Dasatinib	Dasatinib The metabolism of Dasatinib can be increased when combined with Phenytoin.
Mexiletine	Mexiletine The serum concentration of Mexiletine can be decreased when it is combined with Phenytoin.
Armodafinil	Armodafinil The metabolism of Phenytoin can be decreased when combined with Armodafinil.
Ivermectin	Ivermectin The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Ivermectin.
Temsirolimus	Temsirolimus The metabolism of Temsirolimus can be increased when combined with Phenytoin.
Antipyrine-Benzocaine Otic	Antipyrine-Benzocaine Otic The risk or severity of methemoglobinemia can be increased when Phenytoin is combined with Benzocaine.
Maraviroc	Maraviroc The metabolism of Maraviroc can be increased when combined with Phenytoin.
Nilotinib	Nilotinib The metabolism of Phenytoin can be decreased when combined with Nilotinib.
Raltegravir	Raltegravir The metabolism of Raltegravir can be increased when combined with Phenytoin.
Bexarotene	Bexarotene The metabolism of Bexarotene can be decreased when combined with Phenytoin.
Budesonide	Budesonide The serum concentration of Phenytoin can be decreased when it is combined with Budesonide.
Chloramphenicol Injection	Chloramphenicol Injection The serum concentration of Phenytoin can be increased when it is combined with Chloramphenicol.
OnabotulinumtoxinA Injection	OnabotulinumtoxinA Injection The risk or severity of adverse effects can be increased when Botulinum toxin type A is combined with Phenytoin.
RimabotulinumtoxinB Injection	RimabotulinumtoxinB Injection The risk or severity of adverse effects can be increased when Botulinum Toxin Type B is combined with Phenytoin.
Etravirine	Etravirine The serum concentration of Etravirine can be decreased when it is combined with Phenytoin.
Mitoxantrone Injection	Mitoxantrone Injection The metabolism of Phenytoin can be increased when combined with Mitoxantrone.
Desvenlafaxine	Desvenlafaxine The risk or severity of adverse effects can be increased when Phenytoin is combined with Desvenlafaxine.
Cevimeline	Cevimeline The metabolism of Phenytoin can be decreased when combined with Cevimeline.
Nebivolol	Nebivolol The metabolism of Nebivolol can be decreased when combined with Phenytoin.
Tretinoin	Tretinoin The metabolism of Tretinoin can be decreased when combined with Phenytoin.
Leucovorin Injection	Leucovorin Injection The serum concentration of Phenytoin can be decreased when it is combined with Leucovorin.
Pilocarpine	Pilocarpine The metabolism of Phenytoin can be decreased when combined with Pilocarpine.
Flecainide	Flecainide The metabolism of Phenytoin can be decreased when combined with Flecainide.
Certolizumab Injection	Certolizumab Injection The metabolism of Phenytoin can be increased when combined with Certolizumab pegol.
Ixabepilone Injection	Ixabepilone Injection The metabolism of Ixabepilone can be increased when combined with Phenytoin.
Irinotecan Injection	Irinotecan Injection The metabolism of Irinotecan can be increased when combined with Phenytoin.
Levoleucovorin Injection	Levoleucovorin Injection The serum concentration of Phenytoin can be decreased when it is combined with Levoleucovorin.
Daptomycin Injection	Daptomycin Injection The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Daptomycin is combined with Phenytoin.
Praziquantel	Praziquantel The metabolism of Praziquantel can be increased when combined with Phenytoin.
Mitotane	Mitotane The therapeutic efficacy of Phenytoin can be decreased when used in combination with Mitotane.
Rufinamide	Rufinamide The serum concentration of Phenytoin can be increased when it is combined with Rufinamide.
Midazolam	Midazolam The risk or severity of adverse effects can be increased when Phenytoin is combined with Midazolam.
Naltrexone Injection	Naltrexone Injection The metabolism of Naltrexone can be increased when combined with Phenytoin.
Eltrombopag	Eltrombopag The metabolism of Phenytoin can be decreased when combined with Eltrombopag.
Milnacipran	Milnacipran The metabolism of Milnacipran can be increased when combined with Phenytoin.
Dexlansoprazole	Dexlansoprazole The metabolism of Phenytoin can be decreased when combined with Dexlansoprazole.
Sodium Phosphate	Sodium Phosphate The therapeutic efficacy of Phenytoin can be decreased when used in combination with Sodium phosphate, monobasic.
Fesoterodine	Fesoterodine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Fesoterodine.
Betaxolol	Betaxolol The metabolism of Phenytoin can be decreased when combined with Betaxolol.
Iloperidone	Iloperidone The metabolism of Iloperidone can be increased when combined with Phenytoin.
Prasugrel	Prasugrel The metabolism of Prasugrel can be decreased when combined with Phenytoin.
Lacosamide	Lacosamide The serum concentration of Lacosamide can be decreased when it is combined with Phenytoin.
Everolimus	Everolimus The metabolism of Everolimus can be increased when combined with Phenytoin.
Tolvaptan (low blood sodium)	Tolvaptan (low blood sodium) The metabolism of Tolvaptan can be increased when combined with Phenytoin.
Dronedarone	Dronedarone The metabolism of Dronedarone can be increased when combined with Phenytoin.
AbobotulinumtoxinA Injection	AbobotulinumtoxinA Injection The risk or severity of adverse effects can be increased when Botulinum toxin type A is combined with Phenytoin.
Palonosetron Injection	Palonosetron Injection The risk or severity of adverse effects can be increased when Phenytoin is combined with Palonosetron.
Saxagliptin	Saxagliptin The metabolism of Saxagliptin can be increased when combined with Phenytoin.
Romidepsin Injection	Romidepsin Injection The metabolism of Romidepsin can be increased when combined with Phenytoin.
Tapentadol	Tapentadol Tapentadol may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Topotecan	Topotecan Phenytoin may increase the excretion rate of Topotecan which could result in a lower serum level and potentially a reduction in efficacy.
Golimumab Injection	Golimumab Injection The metabolism of Phenytoin can be increased when combined with Golimumab.
Pazopanib	Pazopanib The metabolism of Phenytoin can be decreased when combined with Pazopanib.
Asenapine	Asenapine The risk or severity of adverse effects can be increased when Phenytoin is combined with Asenapine.
Vigabatrin	Vigabatrin The serum concentration of Phenytoin can be decreased when it is combined with Vigabatrin.
Pitavastatin	Pitavastatin The metabolism of Phenytoin can be decreased when combined with Pitavastatin.
Albendazole	Albendazole The serum concentration of the active metabolites of Albendazole can be reduced when Albendazole is used in combination with Phenytoin resulting in a loss in efficacy.
Ulipristal	Ulipristal The metabolism of Ulipristal can be increased when combined with Phenytoin.
Levonorgestrel	Levonorgestrel The metabolism of Levonorgestrel can be increased when combined with Phenytoin.
Oxymorphone	Oxymorphone The risk or severity of adverse effects can be increased when Phenytoin is combined with Oxymorphone.
Tocilizumab Injection	Tocilizumab Injection The metabolism of Phenytoin can be increased when combined with Tocilizumab.
Fingolimod	Fingolimod The metabolism of Fingolimod can be decreased when combined with Phenytoin.
IncobotulinumtoxinA Injection	IncobotulinumtoxinA Injection The risk or severity of adverse effects can be increased when Botulinum toxin type A is combined with Phenytoin.
Cabazitaxel Injection	Cabazitaxel Injection The metabolism of Cabazitaxel can be decreased when combined with Phenytoin.
Lurasidone	Lurasidone The risk or severity of adverse effects can be increased when Phenytoin is combined with Lurasidone.
Acetaminophen Injection	Acetaminophen Injection Acetaminophen may increase the hepatotoxic activities of Phenytoin.
Vilazodone	Vilazodone The metabolism of Vilazodone can be increased when combined with Phenytoin.
Denileukin Diftitox Injection	Denileukin Diftitox Injection The metabolism of Phenytoin can be decreased when combined with Aldesleukin.
Busulfan Injection	Busulfan Injection The serum concentration of Busulfan can be decreased when it is combined with Phenytoin.
Roflumilast	Roflumilast The metabolism of Roflumilast can be increased when combined with Phenytoin.
Linagliptin	Linagliptin The metabolism of Linagliptin can be increased when combined with Phenytoin.
Rilpivirine	Rilpivirine The serum concentration of Rilpivirine can be decreased when it is combined with Phenytoin.
Telaprevir	Telaprevir The metabolism of Phenytoin can be decreased when combined with Glecaprevir.
Cyclophosphamide Injection	Cyclophosphamide Injection The metabolism of Cyclophosphamide can be decreased when combined with Phenytoin.
Abiraterone	Abiraterone The metabolism of Abiraterone can be increased when combined with Phenytoin.
Rivaroxaban	Rivaroxaban The metabolism of Rivaroxaban can be increased when combined with Phenytoin.
Ticagrelor	Ticagrelor The metabolism of Phenytoin can be decreased when combined with Ticagrelor.
Brentuximab Vedotin Injection	Brentuximab Vedotin Injection The metabolism of Brentuximab vedotin can be increased when combined with Phenytoin.
Ruxolitinib	Ruxolitinib The metabolism of Ruxolitinib can be increased when combined with Phenytoin.
Vandetanib	Vandetanib The metabolism of Vandetanib can be increased when combined with Phenytoin.
Clobazam	Clobazam The metabolism of Clobazam can be decreased when combined with Phenytoin.
Vemurafenib	Vemurafenib The metabolism of Phenytoin can be decreased when combined with Vemurafenib.
Vismodegib	Vismodegib The metabolism of Phenytoin can be decreased when combined with Vismodegib.
Ivacaftor	Ivacaftor The serum concentration of Ivacaftor can be decreased when it is combined with Phenytoin.
Deferiprone	Deferiprone The serum concentration of Deferiprone can be increased when it is combined with Phenytoin.
Axitinib	Axitinib The metabolism of Axitinib can be increased when combined with Phenytoin.
Crizotinib	Crizotinib The metabolism of Phenytoin can be increased when combined with Crizotinib.
Cabergoline	Cabergoline The metabolism of Phenytoin can be increased when combined with Cabergoline.
Naloxone Injection	Naloxone Injection The metabolism of Naloxone can be increased when combined with Phenytoin.
Ambrisentan	Ambrisentan The metabolism of Ambrisentan can be increased when combined with Phenytoin.
Ezogabine	Ezogabine The risk or severity of adverse effects can be increased when Phenytoin is combined with Tiagabine.
Iloprost	Iloprost The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Iloprost.
Enzalutamide	Enzalutamide The metabolism of Phenytoin can be decreased when combined with Enzalutamide.
Asparaginase Erwinia Chrysanthemi Injection	Asparaginase Erwinia Chrysanthemi Injection The therapeutic efficacy of Phenytoin can be increased when used in combination with Asparaginase Erwinia chrysanthemi.
Mirabegron	Mirabegron The metabolism of Phenytoin can be decreased when combined with Mirabegron.
Regorafenib	Regorafenib The metabolism of Phenytoin can be decreased when combined with Regorafenib.
Bosutinib	Bosutinib The metabolism of Phenytoin can be decreased when combined with Bosutinib.
Corticotropin, Repository Injection	Corticotropin, Repository Injection The serum concentration of Corticotropin can be decreased when it is combined with Phenytoin.
Teriflunomide	Teriflunomide The metabolism of Phenytoin can be decreased when combined with Teriflunomide.
Cabozantinib (thyroid cancer)	Cabozantinib (thyroid cancer) The metabolism of Cabozantinib can be increased when combined with Phenytoin.
Alogliptin	Alogliptin The metabolism of Alogliptin can be decreased when combined with Phenytoin.
Ponatinib	Ponatinib The metabolism of Ponatinib can be decreased when combined with Phenytoin.
Pomalidomide	Pomalidomide The metabolism of Pomalidomide can be increased when combined with Phenytoin.
Ado-trastuzumab Emtansine Injection	Ado-trastuzumab Emtansine Injection The metabolism of Trastuzumab emtansine can be increased when combined with Phenytoin.
Apixaban	Apixaban The metabolism of Apixaban can be decreased when combined with Phenytoin.
Canagliflozin	Canagliflozin The serum concentration of Canagliflozin can be decreased when it is combined with Phenytoin.
Methazolamide	Methazolamide The risk or severity of osteomalacia can be increased when Methazolamide is combined with Phenytoin.
Dabrafenib	Dabrafenib The serum concentration of Phenytoin can be decreased when it is combined with Dabrafenib.
Ospemifene	Ospemifene The metabolism of Ospemifene can be decreased when combined with Phenytoin.
Trametinib	Trametinib The metabolism of Phenytoin can be decreased when combined with Trametinib.
Dolutegravir	Dolutegravir The metabolism of Dolutegravir can be increased when combined with Phenytoin.
Levomilnacipran	Levomilnacipran The metabolism of Phenytoin can be increased when combined with Levomilnacipran.
Vortioxetine	Vortioxetine The metabolism of Vortioxetine can be increased when combined with Phenytoin.
Perampanel	Perampanel The metabolism of Perampanel can be increased when combined with Phenytoin.
Ibrutinib	Ibrutinib The metabolism of Ibrutinib can be increased when combined with Phenytoin.
Lomitapide	Lomitapide The metabolism of Lomitapide can be increased when combined with Phenytoin.
Ketorolac Injection	Ketorolac Injection The serum concentration of Phenytoin can be increased when it is combined with Ketorolac.
Dapagliflozin	Dapagliflozin The metabolism of Dapagliflozin can be decreased when combined with Phenytoin.
Apremilast	Apremilast The metabolism of Phenytoin can be increased when combined with Apremilast.
Ceritinib	Ceritinib The metabolism of Ceritinib can be increased when combined with Phenytoin.
Siltuximab Injection	Siltuximab Injection The metabolism of Phenytoin can be increased when combined with Siltuximab.
Eslicarbazepine	Eslicarbazepine The serum concentration of Eslicarbazepine can be decreased when it is combined with Phenytoin.
Belinostat Injection	Belinostat Injection The metabolism of Belinostat can be increased when combined with Phenytoin.
Idelalisib	Idelalisib The metabolism of Idelalisib can be increased when combined with Phenytoin.
Testosterone Injection	Testosterone Injection The metabolism of Phenytoin can be decreased when combined with Testosterone.
Oritavancin Injection	Oritavancin Injection The metabolism of Phenytoin can be decreased when combined with Oritavancin.
Vorapaxar	Vorapaxar The metabolism of Vorapaxar can be increased when combined with Phenytoin.
Hydrocodone	Hydrocodone The metabolism of Hydrocodone can be increased when combined with Phenytoin.
Suvorexant	Suvorexant Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Suvorexant.
Olaparib	Olaparib The metabolism of Olaparib can be increased when combined with Phenytoin.
Methamphetamine	Methamphetamine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Metamfetamine.
Tasimelteon	Tasimelteon The metabolism of Tasimelteon can be increased when combined with Phenytoin.
Riociguat	Riociguat The metabolism of Riociguat can be decreased when combined with Phenytoin.
Nintedanib	Nintedanib The metabolism of Nintedanib can be increased when combined with Phenytoin.
Secukinumab Injection	Secukinumab Injection The metabolism of Phenytoin can be increased when combined with Secukinumab.
Risperidone Injection	Risperidone Injection The metabolism of Risperidone can be increased when combined with Phenytoin.
Palbociclib	Palbociclib The metabolism of Palbociclib can be increased when combined with Phenytoin.
Lenvatinib	Lenvatinib The metabolism of Phenytoin can be decreased when combined with Lenvatinib.
Naloxegol	Naloxegol The metabolism of Phenytoin can be decreased when combined with Naloxegol.
Panobinostat	Panobinostat The metabolism of Phenytoin can be decreased when combined with Panobinostat.
Haloperidol Injection	Haloperidol Injection The risk or severity of CNS depression can be increased when Phenytoin is combined with Haloperidol.
Sonidegib	Sonidegib The metabolism of Sonidegib can be increased when combined with Phenytoin.
Flibanserin	Flibanserin The risk or severity of adverse effects can be increased when Phenytoin is combined with Flibanserin.
Rolapitant	Rolapitant The metabolism of Phenytoin can be decreased when combined with Rolapitant.
Prednisolone	Prednisolone The serum concentration of Phenytoin can be decreased when it is combined with Prednisolone.
Daclatasvir	Daclatasvir The metabolism of Daclatasvir can be increased when combined with Phenytoin.
Brexpiprazole	Brexpiprazole The metabolism of Brexpiprazole can be increased when combined with Phenytoin.
Ziprasidone Injection	Ziprasidone Injection The risk or severity of adverse effects can be increased when Phenytoin is combined with Ziprasidone.
Cariprazine	Cariprazine The risk or severity of adverse effects can be increased when Phenytoin is combined with Cariprazine.
Cobimetinib	Cobimetinib The metabolism of Cobimetinib can be increased when combined with Phenytoin.
Trabectedin Injection	Trabectedin Injection The metabolism of Trabectedin can be decreased when combined with Phenytoin.
Osimertinib	Osimertinib The metabolism of Osimertinib can be increased when combined with Phenytoin.
Alectinib	Alectinib The metabolism of Alectinib can be increased when combined with Phenytoin.
Ixazomib	Ixazomib The metabolism of Ixazomib can be increased when combined with Phenytoin.
Rifapentine	Rifapentine The metabolism of Phenytoin can be increased when combined with Rifapentine.
Lesinurad	Lesinurad The metabolism of Phenytoin can be decreased when combined with Lesinurad.
Amphotericin B Liposomal Injection	Amphotericin B Liposomal Injection The therapeutic efficacy of Phenytoin can be decreased when used in combination with Amphotericin B.
Dexamethasone Injection	Dexamethasone Injection The serum concentration of Dexamethasone can be decreased when it is combined with Phenytoin.
Brivaracetam Injection	Brivaracetam Injection The metabolism of Brivaracetam can be decreased when combined with Phenytoin.
Venetoclax	Venetoclax The metabolism of Venetoclax can be increased when combined with Phenytoin.
Cobicistat	Cobicistat The metabolism of Phenytoin can be decreased when combined with Cobicistat.
Selexipag	Selexipag The metabolism of Phenytoin can be decreased when combined with Selexipag.
Pimavanserin	Pimavanserin The risk or severity of adverse effects can be increased when Phenytoin is combined with Pimavanserin.
Diphenhydramine Injection	Diphenhydramine Injection The metabolism of Phenytoin can be decreased when combined with Diphenhydramine.
Calcifediol	Calcifediol The serum concentration of Calcifediol can be decreased when it is combined with Phenytoin.
Ergocalciferol	Ergocalciferol The serum concentration of Ergocalciferol can be decreased when it is combined with Phenytoin.
Doxercalciferol	Doxercalciferol The serum concentration of Doxercalciferol can be decreased when it is combined with Phenytoin.
Furosemide Injection	Furosemide Injection Phenytoin may decrease the diuretic activities of Furosemide.
Rucaparib	Rucaparib The metabolism of Phenytoin can be decreased when combined with Rucaparib.
Ribociclib	Ribociclib The metabolism of Ribociclib can be increased when combined with Phenytoin.
Brigatinib	Brigatinib The metabolism of Brigatinib can be decreased when combined with Phenytoin.
Doxepin (Insomnia)	Doxepin (Insomnia) The metabolism of Doxepin can be decreased when combined with Phenytoin.
Deutetrabenazine	Deutetrabenazine The metabolism of Deutetrabenazine can be increased when combined with Phenytoin.
Valbenazine	Valbenazine The metabolism of Valbenazine can be increased when combined with Phenytoin.
Deflazacort	Deflazacort The serum concentration of Deflazacort can be decreased when it is combined with Phenytoin.
Safinamide	Safinamide The metabolism of Phenytoin can be decreased when combined with Safinamide.
Midostaurin	Midostaurin The metabolism of Phenytoin can be decreased when combined with Midostaurin.
Neratinib	Neratinib The metabolism of Neratinib can be increased when combined with Phenytoin.
Enasidenib	Enasidenib The metabolism of Phenytoin can be decreased when combined with Enasidenib.
Aprepitant/Fosaprepitant Injection	Aprepitant/Fosaprepitant Injection The metabolism of Fosaprepitant can be increased when combined with Phenytoin.
Copanlisib Injection	Copanlisib Injection The metabolism of Copanlisib can be increased when combined with Phenytoin.
Delafloxacin	Delafloxacin The metabolism of Phenytoin can be increased when combined with Delafloxacin.
Abemaciclib	Abemaciclib The metabolism of Abemaciclib can be increased when combined with Phenytoin.
Acalabrutinib	Acalabrutinib The metabolism of Phenytoin can be increased when combined with Acalabrutinib.
Letermovir	Letermovir The metabolism of Phenytoin can be increased when combined with Letermovir.
Tetrabenazine	Tetrabenazine The metabolism of Tetrabenazine can be decreased when combined with Phenytoin.
Ertugliflozin	Ertugliflozin The metabolism of Ertugliflozin can be decreased when combined with Phenytoin.
Buprenorphine Injection	Buprenorphine Injection Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Buprenorphine.
Apalutamide	Apalutamide The serum concentration of Phenytoin can be increased when it is combined with Apalutamide.
Penicillamine	Penicillamine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Penicillamine.
Fostamatinib	Fostamatinib The metabolism of Fostamatinib can be decreased when combined with Phenytoin.
Avatrombopag	Avatrombopag The metabolism of Phenytoin can be increased when combined with Avatrombopag.
Baricitinib	Baricitinib The metabolism of Baricitinib can be increased when combined with Phenytoin.
Lofexidine	Lofexidine The therapeutic efficacy of Phenytoin can be increased when used in combination with Lofexidine.
Eliglustat	Eliglustat The metabolism of Phenytoin can be decreased when combined with Eliglustat.
Encorafenib	Encorafenib The metabolism of Encorafenib can be decreased when combined with Phenytoin.
Binimetinib	Binimetinib The metabolism of Binimetinib can be increased when combined with Phenytoin.
Ivosidenib	Ivosidenib The metabolism of Phenytoin can be increased when combined with Ivosidenib.
Elagolix	Elagolix The metabolism of Phenytoin can be decreased when combined with Elagolix.
Doravirine	Doravirine The metabolism of Doravirine can be increased when combined with Phenytoin.
Tafenoquine	Tafenoquine The metabolism of Tafenoquine can be decreased when combined with Phenytoin.
Cannabidiol	Cannabidiol The risk or severity of adverse effects can be increased when Cannabidiol is combined with Phenytoin.
Dacomitinib	Dacomitinib The metabolism of Dacomitinib can be increased when combined with Phenytoin.
Duvelisib	Duvelisib The metabolism of Duvelisib can be increased when combined with Phenytoin.
Stiripentol	Stiripentol The serum concentration of Phenytoin can be increased when it is combined with Stiripentol.
Gilteritinib	Gilteritinib The metabolism of Gilteritinib can be increased when combined with Phenytoin.
Glasdegib	Glasdegib The metabolism of Glasdegib can be decreased when combined with Phenytoin.
Lorlatinib	Lorlatinib The metabolism of Phenytoin can be decreased when combined with Lorlatinib.
Paclitaxel (with albumin) Injection	Paclitaxel (with albumin) Injection The serum concentration of Phenytoin can be decreased when it is combined with Paclitaxel.
Rifamycin	Rifamycin The metabolism of Phenytoin can be decreased when combined with Rifamycin.
Prucalopride	Prucalopride The metabolism of Prucalopride can be increased when combined with Phenytoin.
Magnesium Citrate	Magnesium Citrate Magnesium citrate can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Emapalumab-lzsg Injection	Emapalumab-lzsg Injection The metabolism of Phenytoin can be increased when combined with Emapalumab.
Siponimod	Siponimod The therapeutic efficacy of Siponimod can be decreased when used in combination with Phenytoin.
Erdafitinib	Erdafitinib The metabolism of Erdafitinib can be increased when combined with Phenytoin.
Esomeprazole Injection	Esomeprazole Injection The serum concentration of Phenytoin can be increased when it is combined with Esomeprazole.
Alpelisib	Alpelisib The serum concentration of Alpelisib can be decreased when it is combined with Phenytoin.
Brexanolone Injection	Brexanolone Injection The risk or severity of adverse effects can be increased when Phenytoin is combined with Brexanolone.
Cladribine	Cladribine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Cladribine is combined with Phenytoin.
Polatuzumab vedotin-piiq Injection	Polatuzumab vedotin-piiq Injection The risk or severity of adverse effects can be decreased when Phenytoin is combined with Polatuzumab vedotin.
Solriamfetol	Solriamfetol The risk or severity of adverse effects can be increased when Phenytoin is combined with Solriamfetol.
Darolutamide	Darolutamide The serum concentration of Phenytoin can be decreased when it is combined with Darolutamide.
Triclabendazole	Triclabendazole The metabolism of Phenytoin can be decreased when combined with Triclabendazole.
Entrectinib	Entrectinib The metabolism of Entrectinib can be increased when combined with Phenytoin.
Pexidartinib	Pexidartinib The metabolism of Pexidartinib can be increased when combined with Phenytoin.
Upadacitinib	Upadacitinib The metabolism of Upadacitinib can be increased when combined with Phenytoin.
Istradefylline	Istradefylline The metabolism of Phenytoin can be decreased when combined with Istradefylline.
Pitolisant	Pitolisant The metabolism of Pitolisant can be increased when combined with Phenytoin.
Fedratinib	Fedratinib The metabolism of Fedratinib can be increased when combined with Phenytoin.
Lefamulin	Lefamulin The metabolism of Lefamulin can be increased when combined with Phenytoin.
Fosphenytoin Injection	Fosphenytoin Injection The metabolism of Fosphenytoin can be increased when combined with Phenytoin.
Zanubrutinib	Zanubrutinib The metabolism of Zanubrutinib can be increased when combined with Phenytoin.
Voxelotor	Voxelotor The serum concentration of Voxelotor can be decreased when it is combined with Phenytoin.
Avapritinib	Avapritinib The metabolism of Avapritinib can be decreased when combined with Phenytoin.
Lumateperone	Lumateperone The serum concentration of Lumateperone can be decreased when it is combined with Phenytoin.
Lasmiditan	Lasmiditan The risk or severity of adverse effects can be increased when Phenytoin is combined with Lasmiditan.
Ubrogepant	Ubrogepant The serum concentration of Ubrogepant can be decreased when it is combined with Phenytoin.
Tazemetostat	Tazemetostat The metabolism of Tazemetostat can be increased when combined with Phenytoin.
Cenobamate	Cenobamate The serum concentration of Cenobamate can be increased when it is combined with Phenytoin.
Pemigatinib	Pemigatinib The metabolism of Pemigatinib can be increased when combined with Phenytoin.
Ozanimod	Ozanimod The metabolism of Ozanimod can be decreased when combined with Phenytoin.
Selumetinib	Selumetinib The serum concentration of Selumetinib can be decreased when it is combined with Phenytoin.
Rimegepant	Rimegepant The metabolism of Rimegepant can be increased when combined with Phenytoin.
Tucatinib	Tucatinib The metabolism of Tucatinib can be increased when combined with Phenytoin.
Sacituzumab govitecan-hziy Injection	Sacituzumab govitecan-hziy Injection The serum concentration of Sacituzumab govitecan can be decreased when it is combined with Phenytoin.
Ripretinib	Ripretinib The serum concentration of Ripretinib can be decreased when it is combined with Phenytoin.
Selpercatinib	Selpercatinib The serum concentration of Phenytoin can be decreased when it is combined with Selpercatinib.
Capmatinib	Capmatinib The serum concentration of Capmatinib can be decreased when it is combined with Phenytoin.
Lemborexant	Lemborexant The serum concentration of Lemborexant can be decreased when it is combined with Phenytoin.
Daratumumab and Hyaluronidase-fihj Injection	Daratumumab and Hyaluronidase-fihj Injection The therapeutic efficacy of Phenytoin can be decreased when used in combination with Hyaluronidase.
Fenfluramine	Fenfluramine The serum concentration of Fenfluramine can be decreased when it is combined with Phenytoin.
Fostemsavir	Fostemsavir The serum concentration of Fostemsavir can be decreased when it is combined with Phenytoin.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection	Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection The therapeutic efficacy of Phenytoin can be decreased when used in combination with Hyaluronidase.
Lurbinectedin Injection	Lurbinectedin Injection The serum concentration of Lurbinectedin can be decreased when it is combined with Phenytoin.
Pralsetinib	Pralsetinib The serum concentration of Phenytoin can be decreased when it is combined with Pralsetinib.
Opicapone	Opicapone The metabolism of Phenytoin can be decreased when combined with Opicapone.
Satralizumab-mwge Injection	Satralizumab-mwge Injection The serum concentration of Phenytoin can be decreased when it is combined with Satralizumab.
Relugolix	Relugolix The serum concentration of Relugolix can be decreased when it is combined with Phenytoin.
Progestin-Only (drospirenone) Oral Contraceptives	Progestin-Only (drospirenone) Oral Contraceptives The metabolism of Drospirenone can be increased when combined with Phenytoin.
Viloxazine	Viloxazine The risk or severity of adverse effects can be increased when Phenytoin is combined with Viloxazine.
Theophylline	Theophylline The serum concentration of Theophylline can be decreased when it is combined with Phenytoin.
Fenoprofen	Fenoprofen The serum concentration of Phenytoin can be increased when it is combined with Fenoprofen.
Indomethacin	Indomethacin The serum concentration of Phenytoin can be increased when it is combined with Indomethacin.
Mefenamic Acid	Mefenamic Acid The serum concentration of Phenytoin can be increased when it is combined with Mefenamic acid.
Naproxen	Naproxen The serum concentration of Phenytoin can be increased when it is combined with Naproxen.
Tolmetin	Tolmetin The serum concentration of Phenytoin can be increased when it is combined with Tolmetin.
Sulindac	Sulindac The serum concentration of Phenytoin can be increased when it is combined with Sulindac.
Trazodone	Trazodone The serum concentration of Phenytoin can be increased when it is combined with Trazodone.
Isotretinoin	Isotretinoin The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Isotretinoin.
Sucralfate	Sucralfate Sucralfate can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Hydroxyurea	Hydroxyurea The metabolism of Phenytoin can be decreased when combined with Hydroxyurea.
Floxuridine	Floxuridine The serum concentration of Phenytoin can be increased when it is combined with Floxuridine.
Metaxalone	Metaxalone The risk or severity of adverse effects can be increased when Phenytoin is combined with Metaxalone.
Methotrexate Injection	Methotrexate Injection The serum concentration of Methotrexate can be decreased when it is combined with Phenytoin.
Levorphanol	Levorphanol The risk or severity of adverse effects can be increased when Phenytoin is combined with Levorphanol.
Primidone	Primidone The metabolism of Primidone can be increased when combined with Phenytoin.
Methsuximide	Methsuximide The serum concentration of Phenytoin can be increased when it is combined with Methsuximide.
Diethylpropion	Diethylpropion The therapeutic efficacy of Phenytoin can be decreased when used in combination with Diethylpropion.
Chlorpromazine	Chlorpromazine The metabolism of Chlorpromazine can be increased when combined with Phenytoin.
Diazepam	Diazepam The serum concentration of Diazepam can be decreased when it is combined with Phenytoin.
Oxazepam	Oxazepam The metabolism of Oxazepam can be decreased when combined with Phenytoin.
Flurazepam	Flurazepam The risk or severity of adverse effects can be increased when Phenytoin is combined with Flurazepam.
Clorazepate	Clorazepate The risk or severity of adverse effects can be increased when Phenytoin is combined with Clorazepic acid.
Lorazepam	Lorazepam The metabolism of Lorazepam can be increased when combined with Phenytoin.
Carmustine	Carmustine The serum concentration of Phenytoin can be decreased when it is combined with Carmustine.
Codeine	Codeine The risk or severity of adverse effects can be increased when Phenytoin is combined with Codeine.
Meprobamate	Meprobamate The risk or severity of adverse effects can be increased when Phenytoin is combined with Meprobamate.
Chlordiazepoxide	Chlordiazepoxide The serum concentration of Chlordiazepoxide can be increased when it is combined with Phenytoin.
Bromocriptine	Bromocriptine The risk or severity of adverse effects can be increased when Phenytoin is combined with Bromocriptine.
Tranylcypromine	Tranylcypromine The metabolism of Phenytoin can be decreased when combined with Tranylcypromine.
Phenelzine	Phenelzine The metabolism of Phenytoin can be decreased when combined with Phenelzine.
Procarbazine	Procarbazine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Procarbazine.
Ergoloid Mesylates	Ergoloid Mesylates The risk or severity of adverse effects can be increased when Phenytoin is combined with Ergoloid mesylate.
Minocycline	Minocycline Minocycline may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Prochlorperazine	Prochlorperazine The metabolism of Prochlorperazine can be increased when combined with Phenytoin.
Thioridazine	Thioridazine The serum concentration of Thioridazine can be increased when it is combined with Phenytoin.
Trifluoperazine	Trifluoperazine The serum concentration of Phenytoin can be increased when it is combined with Trifluoperazine.
Bleomycin	Bleomycin The serum concentration of Phenytoin can be decreased when it is combined with Bleomycin.
Dapsone	Dapsone The risk or severity of methemoglobinemia can be increased when Dapsone is combined with Phenytoin.
Sulfadiazine	Sulfadiazine The serum concentration of Phenytoin can be increased when it is combined with Sulfadiazine.
Oxycodone	Oxycodone The metabolism of Oxycodone can be increased when combined with Phenytoin.
Methadone	Methadone The risk or severity of adverse effects can be increased when Methadone is combined with Phenytoin.
Oxybutynin	Oxybutynin The metabolism of Oxybutynin can be decreased when combined with Phenytoin.
Benztropine	Benztropine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Benzatropine.
Colestipol	Colestipol Colestipol can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Maprotiline	Maprotiline Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Maprotiline.
Ibuprofen	Ibuprofen The serum concentration of Phenytoin can be increased when it is combined with Ibuprofen.
Trihexyphenidyl	Trihexyphenidyl Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Trihexyphenidyl.
Orphenadrine	Orphenadrine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Orphenadrine.
Perphenazine	Perphenazine The serum concentration of Perphenazine can be increased when it is combined with Phenytoin.
Fluphenazine	Fluphenazine The serum concentration of Phenytoin can be increased when it is combined with Fluphenazine.
Phentermine	Phentermine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Phentermine.
Methylphenidate	Methylphenidate The serum concentration of Phenytoin can be increased when it is combined with Methylphenidate.
Amoxapine	Amoxapine The metabolism of Amoxapine can be decreased when combined with Phenytoin.
Sulfasalazine	Sulfasalazine The serum concentration of Phenytoin can be increased when it is combined with Sulfasalazine.
Hydrocortisone	Hydrocortisone The serum concentration of Hydrocortisone can be decreased when it is combined with Phenytoin.
Doxorubicin	Doxorubicin The metabolism of Phenytoin can be increased when combined with Doxorubicin.
Cytarabine	Cytarabine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Cytarabine.
Phenazopyridine	Phenazopyridine The risk or severity of methemoglobinemia can be increased when Phenytoin is combined with Phenazopyridine.
Carbamazepine	Carbamazepine The serum concentration of Carbamazepine can be decreased when it is combined with Phenytoin.
Molindone	Molindone The risk or severity of adverse effects can be increased when Phenytoin is combined with Molindone.
Methyldopa	Methyldopa The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Methyldopa.
Clonidine	Clonidine The risk or severity of sedation can be increased when Clonidine is combined with Phenytoin.
Cimetidine	Cimetidine The serum concentration of Phenytoin can be increased when it is combined with Cimetidine.
Warfarin	Warfarin The metabolism of Warfarin can be increased when combined with Phenytoin.
Clonazepam	Clonazepam The metabolism of Clonazepam can be increased when combined with Phenytoin.
Loperamide	Loperamide The metabolism of Loperamide can be decreased when combined with Phenytoin.
Promethazine	Promethazine The serum concentration of Phenytoin can be increased when it is combined with Promethazine.
Meclofenamate	Meclofenamate The serum concentration of Phenytoin can be increased when it is combined with Meclofenamic acid.
Daunorubicin	Daunorubicin The metabolism of Phenytoin can be increased when combined with Daunorubicin.
Nitrofurantoin	Nitrofurantoin The risk or severity of methemoglobinemia can be increased when Phenytoin is combined with Nitrofurantoin.
Griseofulvin	Griseofulvin The metabolism of Phenytoin can be increased when combined with Griseofulvin.
Digoxin	Digoxin The serum concentration of Digoxin can be decreased when it is combined with Phenytoin.
Loxapine	Loxapine The risk or severity of adverse effects can be increased when Phenytoin is combined with Loxapine.
Mebendazole	Mebendazole The serum concentration of Mebendazole can be decreased when it is combined with Phenytoin.
Chloroquine	Chloroquine The metabolism of Phenytoin can be decreased when combined with Chloroquine.
Quinine	Quinine The serum concentration of Quinine can be decreased when it is combined with Phenytoin.
Ethosuximide	Ethosuximide The serum concentration of Ethosuximide can be increased when it is combined with Phenytoin.
Calcitriol	Calcitriol The serum concentration of Calcitriol can be decreased when it is combined with Phenytoin.
Sulfinpyrazone	Sulfinpyrazone The metabolism of Phenytoin can be decreased when combined with Sulfinpyrazone.
Isosorbide	Isosorbide The metabolism of Isosorbide can be increased when combined with Phenytoin.
Clindamycin Injection	Clindamycin Injection The metabolism of Clindamycin can be increased when combined with Phenytoin.
Secobarbital	Secobarbital The metabolism of Phenytoin can be increased when combined with Secobarbital.
Desipramine	Desipramine The metabolism of Desipramine can be decreased when combined with Phenytoin.
Amitriptyline	Amitriptyline The metabolism of Amitriptyline can be decreased when combined with Phenytoin.
Imipramine	Imipramine The metabolism of Phenytoin can be decreased when combined with Imipramine.
Probenecid	Probenecid The metabolism of Phenytoin can be decreased when combined with Probenecid.
Quinidine	Quinidine The serum concentration of Quinidine can be decreased when it is combined with Phenytoin.
Procainamide	Procainamide The metabolism of Procainamide can be decreased when combined with Phenytoin.
Isoniazid	Isoniazid The serum concentration of Phenytoin can be increased when it is combined with Isoniazid.
Rifampin	Rifampin The serum concentration of Phenytoin can be decreased when it is combined with Rifampicin.
Disopyramide	Disopyramide The serum concentration of Disopyramide can be decreased when it is combined with Phenytoin.
Valproic Acid	Valproic Acid The serum concentration of Phenytoin can be decreased when it is combined with Valproic acid.
Tamoxifen	Tamoxifen The metabolism of Phenytoin can be decreased when combined with Tamoxifen.
Butabarbital	Butabarbital The risk or severity of adverse effects can be increased when Butabarbital is combined with Phenytoin.
Levothyroxine	Levothyroxine The metabolism of Levothyroxine can be decreased when combined with Phenytoin.
Liothyronine	Liothyronine The metabolism of Liothyronine can be increased when combined with Phenytoin.
Methimazole	Methimazole The metabolism of Phenytoin can be decreased when combined with Methimazole.
Propylthiouracil	Propylthiouracil The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Propylthiouracil.
Chlorpropamide	Chlorpropamide Chlorpropamide may decrease the hypoglycemic activities of Phenytoin.
Tolbutamide	Tolbutamide The serum concentration of Phenytoin can be increased when it is combined with Tolbutamide.
Tolazamide	Tolazamide The therapeutic efficacy of Phenytoin can be decreased when used in combination with Tolazamide.
Dextromethorphan	Dextromethorphan The metabolism of Dextromethorphan can be decreased when combined with Phenytoin.
Cyclobenzaprine	Cyclobenzaprine The risk or severity of CNS depression can be increased when Phenytoin is combined with Cyclobenzaprine.
Niacin	Niacin The therapeutic efficacy of Phenytoin can be increased when used in combination with Niacin.
Baclofen	Baclofen The risk or severity of adverse effects can be increased when Baclofen is combined with Phenytoin.
Doxylamine	Doxylamine Doxylamine may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Cyproheptadine	Cyproheptadine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Cyproheptadine.
Clemastine	Clemastine The risk or severity of adverse effects can be increased when Phenytoin is combined with Clemastine.
Chlorpheniramine	Chlorpheniramine The serum concentration of Chlorpheniramine can be increased when it is combined with Phenytoin.
Brompheniramine	Brompheniramine The risk or severity of adverse effects can be increased when Phenytoin is combined with Dexbrompheniramine.
Meclizine	Meclizine The risk or severity of adverse effects can be increased when Phenytoin is combined with Meclizine.
Dantrolene	Dantrolene The risk or severity of adverse effects can be increased when Phenytoin is combined with Dantrolene.
Chlorzoxazone	Chlorzoxazone The risk or severity of adverse effects can be increased when Phenytoin is combined with Chlorzoxazone.
Carisoprodol	Carisoprodol The risk or severity of adverse effects can be increased when Carisoprodol is combined with Phenytoin.
Methocarbamol	Methocarbamol The risk or severity of adverse effects can be increased when Phenytoin is combined with Methocarbamol.
Pyridoxine	Pyridoxine The metabolism of Phenytoin can be increased when combined with Pyridoxine.
Folic Acid	Folic Acid The serum concentration of Phenytoin can be decreased when it is combined with Folic acid.
Danazol	Danazol The therapeutic efficacy of Phenytoin can be increased when used in combination with Danazol.
Disulfiram	Disulfiram The serum concentration of Disulfiram can be increased when it is combined with Phenytoin.
Propranolol (Cardiovascular)	Propranolol (Cardiovascular) The serum concentration of Propranolol can be decreased when it is combined with Phenytoin.
Minoxidil	Minoxidil The metabolism of Minoxidil can be increased when combined with Phenytoin.
Pseudoephedrine	Pseudoephedrine The therapeutic efficacy of Phenytoin can be decreased when used in combination with Pseudoephedrine.
Nortriptyline	Nortriptyline The metabolism of Nortriptyline can be increased when combined with Phenytoin.
Spironolactone	Spironolactone The metabolism of Phenytoin can be decreased when combined with Spironolactone.
Amphotericin B Injection	Amphotericin B Injection The therapeutic efficacy of Phenytoin can be decreased when used in combination with Amphotericin B.
Mercaptopurine	Mercaptopurine The serum concentration of Mercaptopurine can be decreased when it is combined with Phenytoin.
Nadolol	Nadolol The metabolism of Nadolol can be decreased when combined with Phenytoin.
Butorphanol Injection	Butorphanol Injection The risk or severity of adverse effects can be increased when Phenytoin is combined with Butorphanol.
Nalbuphine Injection	Nalbuphine Injection The risk or severity of adverse effects can be increased when Phenytoin is combined with Nalbuphine.
Cholestyramine Resin	Cholestyramine Resin Cholestyramine can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Allopurinol	Allopurinol The metabolism of Phenytoin can be decreased when combined with Allopurinol.
Trimethobenzamide	Trimethobenzamide The risk or severity of adverse effects can be increased when Phenytoin is combined with Trimethobenzamide.
Flavoxate	Flavoxate Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Flavoxate.
Fluorouracil Injection	Fluorouracil Injection The serum concentration of Phenytoin can be increased when it is combined with Fluorouracil.
Colchicine	Colchicine The metabolism of Phenytoin can be decreased when combined with Colchicine.
Cefazolin Injection	Cefazolin Injection The protein binding of Phenytoin can be decreased when combined with Cefazolin.
Cephalexin	Cephalexin The metabolism of Cephalexin can be increased when combined with Phenytoin.
Acetazolamide	Acetazolamide The risk or severity of osteomalacia can be increased when Acetazolamide is combined with Phenytoin.
Cefotaxime Injection	Cefotaxime Injection The therapeutic efficacy of Phenytoin can be decreased when used in combination with Cefotaxime.
Ketoconazole	Ketoconazole The serum concentration of Phenytoin can be increased when it is combined with Ketoconazole.
Pyrantel	Pyrantel The therapeutic efficacy of Pyrantel can be decreased when used in combination with Phenytoin.
Thiotepa Injection	Thiotepa Injection The metabolism of Phenytoin can be increased when combined with Thiotepa.
Vincristine Injection	Vincristine Injection The serum concentration of Vincristine can be decreased when it is combined with Phenytoin.
Captopril	Captopril The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Captopril.
Vinblastine	Vinblastine The metabolism of Phenytoin can be increased when combined with Vinblastine.
Metoprolol	Metoprolol The metabolism of Metoprolol can be increased when combined with Phenytoin.
Hydroxyzine	Hydroxyzine Hydroxyzine may increase the central nervous system depressant (CNS depressant) activities of Phenytoin.
Thiothixene	Thiothixene The risk or severity of adverse effects can be increased when Phenytoin is combined with Thiothixene.
Aspirin	Aspirin The serum concentration of Phenytoin can be increased when it is combined with Acetylsalicylic acid.
Salsalate	Salsalate The serum concentration of Phenytoin can be increased when it is combined with Salsalate.
Chlorambucil	Chlorambucil The therapeutic efficacy of Phenytoin can be decreased when used in combination with Chlorambucil.
Alprazolam	Alprazolam The serum concentration of Phenytoin can be increased when it is combined with Alprazolam.
Temazepam	Temazepam The risk or severity of adverse effects can be increased when Temazepam is combined with Phenytoin.
Triazolam	Triazolam The risk or severity of adverse effects can be increased when Phenytoin is combined with Triazolam.
Dicyclomine	Dicyclomine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Dicyclomine.
Hyoscyamine	Hyoscyamine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Hyoscyamine.
Propantheline	Propantheline Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Propantheline.
Trimethoprim	Trimethoprim The serum concentration of Trimethoprim can be decreased when it is combined with Phenytoin.
Diltiazem	Diltiazem The metabolism of Phenytoin can be decreased when combined with Diltiazem.
Nifedipine	Nifedipine The serum concentration of Phenytoin can be increased when it is combined with Nifedipine.
Timolol	Timolol The metabolism of Timolol can be increased when combined with Phenytoin.
Verapamil	Verapamil The serum concentration of Verapamil can be decreased when it is combined with Phenytoin.
Atenolol	Atenolol The metabolism of Atenolol can be decreased when combined with Phenytoin.
Pindolol	Pindolol The risk or severity of adverse effects can be increased when Phenytoin is combined with Pindolol.
Cisplatin Injection	Cisplatin Injection Cisplatin can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Diflunisal	Diflunisal The serum concentration of Phenytoin can be increased when it is combined with Diflunisal.
Piroxicam	Piroxicam The serum concentration of Phenytoin can be increased when it is combined with Piroxicam.
Bumetanide	Bumetanide The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Bumetanide.
Streptozocin	Streptozocin The metabolism of Phenytoin can be increased when combined with Streptozocin.
Etoposide	Etoposide The metabolism of Etoposide can be increased when combined with Phenytoin.
Glyburide	Glyburide The therapeutic efficacy of Glyburide can be decreased when used in combination with Phenytoin.
Glipizide	Glipizide The therapeutic efficacy of Glipizide can be decreased when used in combination with Phenytoin.
Pentoxifylline	Pentoxifylline The serum concentration of Pentoxifylline can be decreased when it is combined with Phenytoin.
Pentamidine Injection	Pentamidine Injection The metabolism of Pentamidine can be increased when combined with Phenytoin.
Labetalol	Labetalol The metabolism of Labetalol can be increased when combined with Phenytoin.
Leuprolide Injection	Leuprolide Injection The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Leuprolide is combined with Phenytoin.
Gemfibrozil	Gemfibrozil The metabolism of Phenytoin can be decreased when combined with Gemfibrozil.
Ketoprofen	Ketoprofen The serum concentration of Phenytoin can be increased when it is combined with Ketoprofen.
Pimozide	Pimozide The metabolism of Pimozide can be increased when combined with Phenytoin.
Enalapril	Enalapril The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Enalapril.
Flurbiprofen	Flurbiprofen The serum concentration of Phenytoin can be increased when it is combined with Flurbiprofen.
Amiodarone	Amiodarone The serum concentration of Amiodarone can be decreased when it is combined with Phenytoin.
Buspirone	Buspirone The metabolism of Buspirone can be increased when combined with Phenytoin.
Lovastatin	Lovastatin The metabolism of Phenytoin can be decreased when combined with Lovastatin.
Ciprofloxacin	Ciprofloxacin The therapeutic efficacy of Phenytoin can be decreased when used in combination with Ciprofloxacin.
Mesalamine	Mesalamine The serum concentration of Phenytoin can be increased when it is combined with Mesalazine.
Diclofenac	Diclofenac The serum concentration of Diclofenac can be increased when it is combined with Phenytoin.
Fluoxetine	Fluoxetine The risk or severity of Anticonvulsant Toxicity can be increased when Fluoxetine is combined with Phenytoin.
Nimodipine	Nimodipine The serum concentration of Phenytoin can be decreased when it is combined with Nimodipine.
Clozapine	Clozapine The serum concentration of Phenytoin can be decreased when it is combined with Clozapine.
Estazolam	Estazolam The risk or severity of adverse effects can be increased when Phenytoin is combined with Estazolam.
Idarubicin	Idarubicin The metabolism of Phenytoin can be decreased when combined with Idarubicin.
Ofloxacin	Ofloxacin The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Ofloxacin.
Clarithromycin	Clarithromycin The metabolism of Phenytoin can be decreased when combined with Clarithromycin.
Etodolac	Etodolac The serum concentration of Phenytoin can be increased when it is combined with Etodolac.
Felodipine	Felodipine The metabolism of Phenytoin can be decreased when combined with Felodipine.
Nabumetone	Nabumetone The serum concentration of Phenytoin can be increased when it is combined with Nabumetone.
Pravastatin	Pravastatin The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Pravastatin is combined with Phenytoin.
Simvastatin	Simvastatin The serum concentration of Simvastatin can be decreased when it is combined with Phenytoin.
Amlodipine	Amlodipine The serum concentration of Phenytoin can be increased when it is combined with Amlodipine.
Teniposide Injection	Teniposide Injection The serum concentration of Teniposide can be decreased when it is combined with Phenytoin.
Itraconazole	Itraconazole The serum concentration of Phenytoin can be decreased when it is combined with Itraconazole.
Oxaprozin	Oxaprozin The serum concentration of Phenytoin can be increased when it is combined with Oxaprozin.
Atovaquone	Atovaquone The metabolism of Phenytoin can be decreased when combined with Atovaquone.
Rifabutin	Rifabutin The metabolism of Phenytoin can be increased when combined with Rifabutin.
Sotalol	Sotalol The metabolism of Sotalol can be decreased when combined with Phenytoin.
Zolpidem	Zolpidem Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Zolpidem.
Doxazosin	Doxazosin The metabolism of Doxazosin can be increased when combined with Phenytoin.
Isradipine	Isradipine The serum concentration of Phenytoin can be increased when it is combined with Isradipine.
Omeprazole	Omeprazole The serum concentration of Phenytoin can be increased when it is combined with Omeprazole.
Cisapride	Cisapride The metabolism of Cisapride can be increased when combined with Phenytoin.
Gabapentin	Gabapentin The risk or severity of adverse effects can be increased when Phenytoin is combined with Gabapentin.
Fluvastatin	Fluvastatin The serum concentration of Phenytoin can be increased when it is combined with Fluvastatin.
Venlafaxine	Venlafaxine The metabolism of Phenytoin can be decreased when combined with Venlafaxine.
Nizatidine	Nizatidine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Nizatidine.
Stavudine	Stavudine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Stavudine.
Famciclovir	Famciclovir The metabolism of Famciclovir can be increased when combined with Phenytoin.
Fluvoxamine	Fluvoxamine The serum concentration of Fluvoxamine can be increased when it is combined with Phenytoin.
Nefazodone	Nefazodone The risk or severity of adverse effects can be increased when Phenytoin is combined with Nefazodone.
Lamotrigine	Lamotrigine The serum concentration of Lamotrigine can be decreased when it is combined with Phenytoin.
Losartan	Losartan The metabolism of Phenytoin can be decreased when combined with Losartan.
Tramadol	Tramadol The metabolism of Phenytoin can be increased when combined with Tramadol.
Vinorelbine Injection	Vinorelbine Injection The metabolism of Phenytoin can be increased when combined with Vinorelbine.
Carboplatin Injection	Carboplatin Injection Carboplatin can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Lansoprazole	Lansoprazole The metabolism of Phenytoin can be decreased when combined with Lansoprazole.
Ifosfamide Injection	Ifosfamide Injection The metabolism of Ifosfamide can be increased when combined with Phenytoin.
Pegaspargase Injection	Pegaspargase Injection The therapeutic efficacy of Phenytoin can be increased when used in combination with Pegaspargase.
Nicardipine	Nicardipine The metabolism of Phenytoin can be decreased when combined with Nicardipine.
Bupropion	Bupropion The metabolism of Bupropion can be decreased when combined with Phenytoin.
Ticlopidine	Ticlopidine The serum concentration of Ticlopidine can be decreased when it is combined with Phenytoin.
Saquinavir	Saquinavir The serum concentration of Phenytoin can be decreased when it is combined with Saquinavir.
Nisoldipine	Nisoldipine The serum concentration of Phenytoin can be decreased when it is combined with Nisoldipine.
Lamivudine	Lamivudine The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Phenytoin is combined with Lamivudine.
Riluzole	Riluzole The risk or severity of adverse effects can be increased when Phenytoin is combined with Riluzole.
Glimepiride	Glimepiride The therapeutic efficacy of Phenytoin can be decreased when used in combination with Glimepiride.
Anastrozole	Anastrozole The metabolism of Phenytoin can be decreased when combined with Anastrozole.
Indinavir	Indinavir The serum concentration of Phenytoin can be decreased when it is combined with Indinavir.
Ritonavir	Ritonavir The serum concentration of Ritonavir can be decreased when it is combined with Phenytoin.
Docetaxel Injection	Docetaxel Injection The metabolism of Docetaxel can be increased when combined with Phenytoin.
Clomipramine	Clomipramine The metabolism of Clomipramine can be increased when combined with Phenytoin.
Zafirlukast	Zafirlukast The metabolism of Phenytoin can be increased when combined with Zafirlukast.
Mirtazapine	Mirtazapine Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Mirtazapine.
Topiramate	Topiramate The serum concentration of the active metabolites of Phenytoin can be increased when Phenytoin is used in combination with Topiramate.
Zileuton	Zileuton The metabolism of Zileuton can be decreased when combined with Phenytoin.
Valsartan	Valsartan The metabolism of Phenytoin can be decreased when combined with Valsartan.
Pramipexole	Pramipexole Phenytoin may increase the sedative activities of Pramipexole.
Donepezil	Donepezil The metabolism of Donepezil can be decreased when combined with Phenytoin.
Nelfinavir	Nelfinavir The serum concentration of Nelfinavir can be decreased when it is combined with Phenytoin.
Azithromycin	Azithromycin The metabolism of Azithromycin can be increased when combined with Phenytoin.
Loratadine	Loratadine The metabolism of Phenytoin can be decreased when combined with Loratadine.
Carvedilol	Carvedilol The metabolism of Phenytoin can be decreased when combined with Carvedilol.
Nilutamide	Nilutamide The metabolism of Phenytoin can be decreased when combined with Nilutamide.
Flutamide	Flutamide The risk or severity of methemoglobinemia can be increased when Phenytoin is combined with Flutamide.
Selegiline	Selegiline The metabolism of Selegiline can be decreased when combined with Phenytoin.
Bicalutamide	Bicalutamide The metabolism of Phenytoin can be decreased when combined with Bicalutamide.
Sertraline	Sertraline The serum concentration of Phenytoin can be increased when it is combined with Sertraline.
Propafenone	Propafenone The metabolism of Phenytoin can be decreased when combined with Propafenone.
Letrozole	Letrozole The metabolism of Letrozole can be decreased when combined with Phenytoin.
Raloxifene	Raloxifene The metabolism of Phenytoin can be decreased when combined with Raloxifene.
Irbesartan	Irbesartan The metabolism of Phenytoin can be decreased when combined with Irbesartan.
Tamsulosin	Tamsulosin The metabolism of Tamsulosin can be decreased when combined with Phenytoin.
Ropinirole	Ropinirole The metabolism of Ropinirole can be increased when combined with Phenytoin.
Finasteride	Finasteride The metabolism of Finasteride can be increased when combined with Phenytoin.
Quetiapine	Quetiapine The metabolism of Quetiapine can be increased when combined with Phenytoin.
Cetirizine	Cetirizine The risk or severity of adverse effects can be increased when Phenytoin is combined with Cetirizine.
Paroxetine	Paroxetine The serum concentration of Phenytoin can be decreased when it is combined with Paroxetine.
Tolcapone	Tolcapone The metabolism of Phenytoin can be decreased when combined with Tolcapone.
Citalopram	Citalopram The metabolism of Citalopram can be decreased when combined with Phenytoin.
Capecitabine	Capecitabine The serum concentration of Phenytoin can be increased when it is combined with Capecitabine.
Efavirenz	Efavirenz The serum concentration of Efavirenz can be decreased when it is combined with Phenytoin.
Abacavir	Abacavir The metabolism of Abacavir can be increased when combined with Phenytoin.
Sildenafil	Sildenafil The metabolism of Phenytoin can be decreased when combined with Sildenafil.
Pioglitazone	Pioglitazone The metabolism of Pioglitazone can be increased when combined with Phenytoin.
Celecoxib	Celecoxib The serum concentration of Celecoxib can be increased when it is combined with Phenytoin.
Rosiglitazone	Rosiglitazone The metabolism of Rosiglitazone can be decreased when combined with Phenytoin.
Tolterodine	Tolterodine The metabolism of Tolterodine can be decreased when combined with Phenytoin.
Thalidomide	Thalidomide Phenytoin may increase the central nervous system depressant (CNS depressant) activities of Thalidomide.
Aluminum Hydroxide	Aluminum Hydroxide Aluminum hydroxide can cause a decrease in the absorption of Phenytoin resulting in a reduced serum concentration and potentially a decrease in efficacy.
Colesevelam	Colesevelam The serum concentration of Phenytoin can be decreased when it is combined with Colesevelam.
Balsalazide	Balsalazide The serum concentration of Phenytoin can be increased when it is combined with Balsalazide.
Nateglinide	Nateglinide The metabolism of Nateglinide can be decreased when combined with Phenytoin.
Galantamine	Galantamine The metabolism of Galantamine can be decreased when combined with Phenytoin.
Levetiracetam	Levetiracetam The risk or severity of adverse effects can be increased when Phenytoin is combined with Levetiracetam.
Rabeprazole	Rabeprazole The metabolism of Phenytoin can be decreased when combined with Rabeprazole.
Terbinafine	Terbinafine The metabolism of Terbinafine can be decreased when combined with Phenytoin.