Levothyroxine

Generic name: Pronounced as (lee voe thye rox' een)
Brand names
  • Levo-T®
  • Levothroid®
  • Levoxyl®
  • Synthroid®
  • Tirosint®
  • Unithroid®
Click on drug name to hear pronunciation

Medical Content Reviewed By HelloPharmacist Staff

Last Revised - 02/15/2019

Levothyroxine (a thyroid hormone) should not be used alone or along with other treatments to treat obesity or cause weight loss.

Levothyroxine may cause serious or life-threatening problems when given in large doses, especially when taken with amphetamines such as amphetamine (Adzenys, Dyanavel XR, Evekeo), dextroamphetamine (Dexedrine), and methamphetamine (Desoxyn). Tell your doctor if you have any of the following symptoms while you are taking levothyroxine: chest pain, rapid or irregular heartbeat or pulse, uncontrollable shaking of a part of the body, nervousness, anxiety, irritability, difficulty falling asleep or staying asleep, shortness of breath, or excessive sweating.

Talk to your doctor about the potential risks associated with this medication.

Levothyroxine is used to treat hypothyroidism (condition where the thyroid gland does not produce enough thyroid hormone). It is also used with surgery and radioactive iodine therapy to treat thyroid cancer. Levothyroxine is in a class of medications called hormones. It works by replacing thyroid hormone that is normally produced by the body.

Without thyroid hormone, your body cannot function properly, which may result in poor growth, slow speech, lack of energy, excessive tiredness, constipation, weight gain, hair loss, dry, thick skin, increased sensitivity to cold, joint and muscle pain, heavy or irregular menstrual periods, and depression. When taken correctly, levothyroxine reverses these symptoms.

Levothyroxine comes as a tablet and a capsule to take by mouth. It usually is taken once a day on an empty stomach, 30 minutes to 1 hour before breakfast. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take levothyroxine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow capsules whole; do not chew or crush them. Do not remove the capsule from the package until you are ready to take it.

Take the tablets with a full glass of water as they may get stuck in your throat or cause choking or gagging.

If you are giving levothyroxine to an infant, child, or adult who cannot swallow the tablet, crush and mix it in 1 to 2 teaspoons (5 to 10 mL) of water. Only mix the crushed tablets with water; do not mix it with food or soybean infant formula. Give this mixture by spoon or dropper right away. Do not store it for later use.

Your doctor will probably start you on a low dose of levothyroxine and gradually increase your dose.

Levothyroxine controls hypothyroidism but does not cure it. It may take several weeks before you notice a change in your symptoms. Continue to take levothyroxine even if you feel well. Do not stop taking levothyroxine without talking to your doctor.

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

Before taking levothyroxine,

  • tell your doctor and pharmacist if you are allergic to levothyroxine, thyroid hormone, any other medications, or any of the ingredients in levothyroxine tablets or capsules. Ask your pharmacist for a list of the ingredients.

  • 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 or those listed in the IMPORTANT WARNING section: amiodarone (Nexterone, Pacerone); androgens such as nandrolone and testosterone (Androderm); certain antacids containing aluminum or magnesium (Maalox, Mylanta, others); anticoagulants ('blood thinners') such as heparin or warfarin (Coumadin, Jantoven); beta-blockers such as metoprolol (Lopressor), propranolol (Inderal, Innopran), or timolol; medications for cancer such as asparaginase, fluorouracil, and mitotane (Lysodren); carbamazepine (Carbatrol, Equetro, Tegretol, or Teril); clofibrate (Atromid); corticosteroids such as dexamethasone; medications for cough and cold symptoms or for weight loss; digoxin (Lanoxin); medications containing estrogen such as hormone replacement therapy or hormonal contraceptives (birth control pills, patches, rings, implants, or injections); furosemide (Lasix); insulin or other medications to treat diabetes; maprotiline; mefenamic acid (Ponstel); methadone (Methadose); niacin; orlistat (Alli, Xenical); phenobarbital; phenytoin (Dilantin, Phenytek); proton pump inhibitors such as esomeprazole (Nexium), lansoprazole (Prevacid), and omeprazole (Prilosec); rifampin (Rifater, Rifamate, Rifadin); sertraline (Zoloft); simethicone (Phazyme, Gas X); sucralfate (Carafate); tamoxifen (Soltamox); tyrosine kinase inhibitors such as cabozantinib (Cometriq) or imatinib (Gleevac); and tricyclic antidepressants such as amitriptyline (Elavil). Many other medications may also interact with levothyroxine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

  • if you take calcium carbonate (Tums) or ferrous sulfate (iron supplement), take it at least 4 hours before or 4 hours after you take levothyroxine. If you take cholestyramine (Prevalite), colesevelam (Welchol), colestipol (Colestid), sevelamer (Renvela, Renagel), or sodium polystyrene sulfonate (Kayexalate), take it at least 4 hours after you take levothyroxine.

  • tell your doctor if you have adrenal insufficiency (condition in which the adrenal glands do not produce enough of certain hormones needed for important body functions). Your doctor may tell you not to take levothyroxine.

  • tell your doctor if you have recently received radiation therapy or if you have or have ever had diabetes; hardening of the arteries (atherosclerosis); bleeding problems or anemia; porphyria (condition in which abnormal substances build up in the blood and cause problems with the skin or nervous system); osteoporosis (a condition in which the bones become thin and weak and break easily); pituitary gland (a small gland in the brain) disorders; any condition that makes it difficult for you to swallow; or kidney, heart, or liver disease.

  • tell your doctor if you are pregnant, plan to become pregnant or are breastfeeding. If you become pregnant while taking levothyroxine, call your doctor.

  • if you have surgery, including dental surgery, tell the doctor or dentist that you are taking levothyroxine.

Some foods and beverages, particularly those that contain soybeans, walnuts, and dietary fiber, may affect how levothyroxine works for you. Talk to your doctor before eating or drinking these foods.

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

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

    • weight gain or loss

    • headache

    • vomiting

    • diarrhea

    • changes in appetite

    • fever

    • changes in menstrual cycle

    • sensitivity to heat

    • hair loss

    • joint pain

    • leg cramps

  • Some side effects can be serious. If you experience either of the following symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately or get emergency medical treatment:

    • shortness of breath, wheezing, hives, itching, rash, flushing, stomach pain, nausea, or swelling of hands, feet, ankles, or lower legs

  • 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).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

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:

  • chest pain

  • rapid or irregular heartbeat or pulse

  • uncontrollable shaking of a part of the body

  • nervousness

  • anxiety

  • irritability

  • difficulty falling asleep or staying asleep

  • shortness of breath

  • excessive sweating

  • confusion

  • loss of consciousness

  • seizure

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to levothyroxine.

Learn the brand name and generic name of your medication. Do not switch brands without talking to your doctor or pharmacist, as each brand of levothyroxine contains a slightly different amount of medication.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

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 therapeutic efficacy of Levothyroxine can be decreased when used in combination with Repaglinide.
Montelukast Montelukast The metabolism of Montelukast can be decreased when combined with Levothyroxine.
Insulin Glargine (rDNA origin) Injection Insulin Glargine (rDNA origin) Injection The therapeutic efficacy of Insulin glargine can be decreased when used in combination with Levothyroxine.
Atorvastatin Atorvastatin The metabolism of Levothyroxine can be decreased when combined with Atorvastatin.
Aminophylline Aminophylline Levothyroxine may increase the excretion rate of Aminophylline which could result in a lower serum level and potentially a reduction in efficacy.
Calcium Carbonate Calcium Carbonate Calcium carbonate can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Erythromycin and Sulfisoxazole Erythromycin and Sulfisoxazole The excretion of Erythromycin can be decreased when combined with Levothyroxine.
Estrogen and Progestin (Oral Contraceptives) Estrogen and Progestin (Oral Contraceptives) The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Conjugated estrogens.
Magnesium Hydroxide Magnesium Hydroxide Magnesium hydroxide can cause a decrease in the absorption of Levothyroxine 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 Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Miglitol Miglitol The therapeutic efficacy of Miglitol can be decreased when used in combination with Levothyroxine.
Naratriptan Naratriptan Levothyroxine may increase the vasoconstricting activities of Naratriptan.
Olsalazine Olsalazine The therapeutic efficacy of Levothyroxine can be increased when used in combination with Olsalazine.
Paregoric Paregoric The metabolism of Morphine can be decreased when combined with Levothyroxine.
Penbutolol Penbutolol The risk or severity of adverse effects can be increased when Acebutolol is combined with Levothyroxine.
Prednisone Prednisone The therapeutic efficacy of Levothyroxine can be increased when used in combination with Prednisone.
Ranitidine Ranitidine Ranitidine can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Sumatriptan Sumatriptan Levothyroxine may increase the vasoconstricting activities of Sumatriptan.
Triamcinolone Triamcinolone The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Triamcinolone.
Famotidine Injection Famotidine Injection Famotidine can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Metoclopramide Injection Metoclopramide Injection The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Metoclopramide.
Morphine Injection Morphine Injection The metabolism of Morphine can be decreased when combined with Levothyroxine.
Zidovudine Injection Zidovudine Injection The metabolism of Levothyroxine can be increased when combined with Zidovudine.
Altretamine Altretamine The risk or severity of adverse effects can be increased when Amphetamine is combined with Levothyroxine.
Cyclosporine Cyclosporine The serum concentration of Cyclosporine can be decreased when it is combined with Levothyroxine.
Torsemide Torsemide The metabolism of Torasemide can be decreased when combined with Levothyroxine.
Hydroxychloroquine Hydroxychloroquine The metabolism of Hydroxychloroquine can be decreased when combined with Levothyroxine.
Orlistat Orlistat The serum concentration of Levothyroxine can be decreased when it is combined with Orlistat.
Pantoprazole Pantoprazole Pantoprazole can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Sevelamer Sevelamer The serum concentration of Levothyroxine can be decreased when it is combined with Sevelamer.
Trimipramine Trimipramine The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Trimipramine.
Sirolimus Sirolimus The serum concentration of Levothyroxine can be decreased when it is combined with Sirolimus.
Epinephrine Injection Epinephrine Injection The therapeutic efficacy of Epinephrine can be increased when used in combination with Levothyroxine.
Escitalopram Escitalopram The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Escitalopram.
Atazanavir Atazanavir The metabolism of Levothyroxine can be decreased when combined with Atazanavir.
Almotriptan Almotriptan The metabolism of Almotriptan can be decreased when combined with Levothyroxine.
Apomorphine Injection Apomorphine Injection The metabolism of Apomorphine can be decreased when combined with Levothyroxine.
Oxandrolone Oxandrolone The therapeutic efficacy of Levothyroxine can be increased when used in combination with Oxandrolone.
Protriptyline Protriptyline The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Protriptyline.
Duloxetine Duloxetine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Duloxetine.
Erlotinib Erlotinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Erlotinib.
Eszopiclone Eszopiclone The metabolism of Eszopiclone can be decreased when combined with Levothyroxine.
Insulin Aspart (rDNA Origin) Injection Insulin Aspart (rDNA Origin) Injection The therapeutic efficacy of Insulin aspart can be decreased when used in combination with Levothyroxine.
Dextroamphetamine Dextroamphetamine The risk or severity of adverse effects can be increased when Amphetamine is combined with Levothyroxine.
Pramlintide Injection Pramlintide Injection The therapeutic efficacy of Pramlintide can be decreased when used in combination with Levothyroxine.
Exenatide Injection Exenatide Injection The therapeutic efficacy of Exenatide can be decreased when used in combination with Levothyroxine.
Deferasirox Deferasirox The metabolism of Levothyroxine can be decreased when combined with Deferasirox.
Phenylephrine Phenylephrine The risk or severity of adverse effects can be increased when Phenylephrine is combined with Levothyroxine.
Tipranavir Tipranavir The metabolism of Levothyroxine can be increased when combined with Tipranavir.
Insulin Detemir (rDNA Origin) Injection Insulin Detemir (rDNA Origin) Injection The therapeutic efficacy of Insulin detemir can be decreased when used in combination with Levothyroxine.
Imatinib Imatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Imatinib.
Sitagliptin Sitagliptin The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Levothyroxine.
Gefitinib Gefitinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Gefitinib.
Paliperidone Paliperidone The serum concentration of Paliperidone can be decreased when it is combined with Levothyroxine.
Bortezomib Bortezomib The serum concentration of Bortezomib can be decreased when it is combined with Levothyroxine.
Insulin Glulisine (rDNA origin) Injection Insulin Glulisine (rDNA origin) Injection The therapeutic efficacy of Insulin glulisine can be decreased when used in combination with Levothyroxine.
Bismuth Subsalicylate Bismuth Subsalicylate The therapeutic efficacy of Levothyroxine can be increased when used in combination with Bismuth subsalicylate.
Lisdexamfetamine Lisdexamfetamine The risk or severity of adverse effects can be increased when Lisdexamfetamine is combined with Levothyroxine.
Sorafenib Sorafenib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Sorafenib.
Sunitinib Sunitinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Sunitinib.
Lapatinib Lapatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Lapatinib.
Dasatinib Dasatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Dasatinib.
Temsirolimus Temsirolimus The serum concentration of Levothyroxine can be decreased when it is combined with Temsirolimus.
Nilotinib Nilotinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Nilotinib.
Desvenlafaxine Desvenlafaxine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Desvenlafaxine.
Nebivolol Nebivolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Nebivolol.
Tretinoin Tretinoin The metabolism of Tretinoin can be decreased when combined with Levothyroxine.
Bendamustine Injection Bendamustine Injection The serum concentration of Bendamustine can be decreased when it is combined with Levothyroxine.
Mitotane Mitotane The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Mitotane.
Eltrombopag Eltrombopag The metabolism of Levothyroxine can be decreased when combined with Eltrombopag.
Milnacipran Milnacipran The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Milnacipran.
Dexlansoprazole Dexlansoprazole Dexlansoprazole can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Betaxolol Betaxolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Betaxolol.
Everolimus Everolimus The serum concentration of Everolimus can be decreased when it is combined with Levothyroxine.
Tolvaptan (low blood sodium) Tolvaptan (low blood sodium) The serum concentration of Tolvaptan can be decreased when it is combined with Levothyroxine.
Saxagliptin Saxagliptin The therapeutic efficacy of Saxagliptin can be decreased when used in combination with Levothyroxine.
Romidepsin Injection Romidepsin Injection The serum concentration of Romidepsin can be decreased when it is combined with Levothyroxine.
Topotecan Topotecan The serum concentration of Topotecan can be decreased when it is combined with Levothyroxine.
Pazopanib Pazopanib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Pazopanib.
Pitavastatin Pitavastatin The metabolism of Pitavastatin can be decreased when combined with Levothyroxine.
Liraglutide Injection Liraglutide Injection The therapeutic efficacy of Liraglutide can be decreased when used in combination with Levothyroxine.
Cabazitaxel Injection Cabazitaxel Injection The serum concentration of Cabazitaxel can be decreased when it is combined with Levothyroxine.
Denileukin Diftitox Injection Denileukin Diftitox Injection The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Aldesleukin.
Terbutaline Injection Terbutaline Injection The risk or severity of adverse effects can be increased when Terbutaline is combined with Levothyroxine.
Linagliptin Linagliptin The therapeutic efficacy of Linagliptin can be decreased when used in combination with Levothyroxine.
Telaprevir Telaprevir The metabolism of Levothyroxine can be decreased when combined with Glecaprevir.
Cyclophosphamide Injection Cyclophosphamide Injection The metabolism of Cyclophosphamide can be decreased when combined with Levothyroxine.
Brentuximab Vedotin Injection Brentuximab Vedotin Injection The serum concentration of Brentuximab vedotin can be decreased when it is combined with Levothyroxine.
Ruxolitinib Ruxolitinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Ruxolitinib.
Vandetanib Vandetanib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Vandetanib.
Vemurafenib Vemurafenib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Vemurafenib.
Axitinib Axitinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Axitinib.
Crizotinib Crizotinib The therapeutic efficacy of Crizotinib can be decreased when used in combination with Levothyroxine.
Cabergoline Cabergoline The serum concentration of Cabergoline can be decreased when it is combined with Levothyroxine.
Ambrisentan Ambrisentan The excretion of Levothyroxine can be decreased when combined with Ambrisentan.
Carfilzomib Injection Carfilzomib Injection The serum concentration of Carfilzomib can be decreased when it is combined with Levothyroxine.
Enzalutamide Enzalutamide The metabolism of Enzalutamide can be decreased when combined with Levothyroxine.
Asparaginase Erwinia Chrysanthemi Injection Asparaginase Erwinia Chrysanthemi Injection The therapeutic efficacy of Levothyroxine can be increased when used in combination with Asparaginase Erwinia chrysanthemi.
Regorafenib Regorafenib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Regorafenib.
Bosutinib Bosutinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Bosutinib.
Lorcaserin Lorcaserin The therapeutic efficacy of Mecasermin can be decreased when used in combination with Levothyroxine.
Cabozantinib (thyroid cancer) Cabozantinib (thyroid cancer) The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Cabozantinib.
Alogliptin Alogliptin The therapeutic efficacy of Alogliptin can be decreased when used in combination with Levothyroxine.
Ponatinib Ponatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Ponatinib.
Pomalidomide Pomalidomide The serum concentration of Pomalidomide can be decreased when it is combined with Levothyroxine.
Ado-trastuzumab Emtansine Injection Ado-trastuzumab Emtansine Injection The serum concentration of Trastuzumab emtansine can be decreased when it is combined with Levothyroxine.
Apixaban Apixaban The metabolism of Apixaban can be decreased when combined with Levothyroxine.
Canagliflozin Canagliflozin The therapeutic efficacy of Canagliflozin can be decreased when used in combination with Levothyroxine.
Dabrafenib Dabrafenib The serum concentration of Dabrafenib can be decreased when it is combined with Levothyroxine.
Afatinib Afatinib The serum concentration of Afatinib can be decreased when it is combined with Levothyroxine.
Levomilnacipran Levomilnacipran The metabolism of Levothyroxine can be decreased when combined with Levomilnacipran.
Vortioxetine Vortioxetine The metabolism of Vortioxetine can be decreased when combined with Levothyroxine.
Ibrutinib Ibrutinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Ibrutinib.
Ketorolac Injection Ketorolac Injection The metabolism of Ketorolac can be decreased when combined with Levothyroxine.
Simeprevir Simeprevir The excretion of Simeprevir can be decreased when combined with Levothyroxine.
Sofosbuvir Sofosbuvir The serum concentration of Sofosbuvir can be decreased when it is combined with Levothyroxine.
Dapagliflozin Dapagliflozin The therapeutic efficacy of Dapagliflozin can be decreased when used in combination with Levothyroxine.
Iron Sucrose Injection Iron Sucrose Injection The serum concentration of Levothyroxine can be decreased when it is combined with Iron sucrose.
Droxidopa Droxidopa The therapeutic efficacy of Droxidopa can be increased when used in combination with Levothyroxine.
Ceritinib Ceritinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Ceritinib.
Albiglutide Injection Albiglutide Injection The therapeutic efficacy of Albiglutide can be decreased when used in combination with Levothyroxine.
Iron Dextran Injection Iron Dextran Injection Iron Dextran can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Testosterone Injection Testosterone Injection The therapeutic efficacy of Testosterone can be increased when used in combination with Levothyroxine.
Empagliflozin Empagliflozin The therapeutic efficacy of Empagliflozin can be decreased when used in combination with Levothyroxine.
Dulaglutide Injection Dulaglutide Injection The therapeutic efficacy of Dulaglutide can be decreased when used in combination with Levothyroxine.
Caspofungin Injection Caspofungin Injection The excretion of Caspofungin can be decreased when combined with Levothyroxine.
Methamphetamine Methamphetamine The risk or severity of adverse effects can be increased when Metamfetamine is combined with Levothyroxine.
Riociguat Riociguat The metabolism of Riociguat can be decreased when combined with Levothyroxine.
Nintedanib Nintedanib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Nintedanib.
Insulin Human Inhalation Insulin Human Inhalation The therapeutic efficacy of Insulin human can be decreased when used in combination with Levothyroxine.
Lenvatinib Lenvatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Lenvatinib.
Panobinostat Panobinostat The serum concentration of Panobinostat can be decreased when it is combined with Levothyroxine.
Insulin Degludec (rDNA Origin) Injection Insulin Degludec (rDNA Origin) Injection The therapeutic efficacy of Insulin degludec can be decreased when used in combination with Levothyroxine.
Cobimetinib Cobimetinib The serum concentration of Levothyroxine can be decreased when it is combined with Cobimetinib.
Osimertinib Osimertinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Osimertinib.
Alectinib Alectinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Alectinib.
Patiromer Patiromer Patiromer can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Venetoclax Venetoclax The serum concentration of Venetoclax can be decreased when it is combined with Levothyroxine.
Midodrine Midodrine The risk or severity of adverse effects can be increased when Midodrine is combined with Levothyroxine.
Selexipag Selexipag The metabolism of Levothyroxine can be decreased when combined with Selexipag.
Furosemide Injection Furosemide Injection The protein binding of Furosemide can be decreased when combined with Levothyroxine.
Rucaparib Rucaparib The metabolism of Levothyroxine can be decreased when combined with Rucaparib.
Lixisenatide Injection Lixisenatide Injection The therapeutic efficacy of Lixisenatide can be decreased when used in combination with Levothyroxine.
Brigatinib Brigatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Brigatinib.
Doxepin (Insomnia) Doxepin (Insomnia) The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Doxepin.
Deflazacort Deflazacort The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Deflazacort.
Midostaurin Midostaurin The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Midostaurin.
Neratinib Neratinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Neratinib.
Enasidenib Enasidenib The metabolism of Enasidenib can be decreased when combined with Levothyroxine.
Inotuzumab Ozogamicin Injection Inotuzumab Ozogamicin Injection The serum concentration of Inotuzumab ozogamicin can be decreased when it is combined with Levothyroxine.
Copanlisib Injection Copanlisib Injection The serum concentration of Copanlisib can be decreased when it is combined with Levothyroxine.
Abemaciclib Abemaciclib The serum concentration of Abemaciclib can be decreased when it is combined with Levothyroxine.
Acalabrutinib Acalabrutinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Acalabrutinib.
Letermovir Letermovir The excretion of Letermovir can be decreased when combined with Levothyroxine.
Semaglutide Injection Semaglutide Injection The serum concentration of Semaglutide can be increased when it is combined with Levothyroxine.
Ertugliflozin Ertugliflozin The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Ertugliflozin.
Buprenorphine Injection Buprenorphine Injection The metabolism of Buprenorphine can be decreased when combined with Levothyroxine.
Apalutamide Apalutamide The metabolism of Apalutamide can be decreased when combined with Levothyroxine.
Fostamatinib Fostamatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Fostamatinib.
Sodium Zirconium Cyclosilicate Sodium Zirconium Cyclosilicate Sodium zirconium cyclosilicate can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Binimetinib Binimetinib The serum concentration of Binimetinib can be decreased when it is combined with Levothyroxine.
Elagolix Elagolix The metabolism of Elagolix can be decreased when combined with Levothyroxine.
Dacomitinib Dacomitinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Dacomitinib.
Talazoparib Talazoparib The serum concentration of Talazoparib can be decreased when it is combined with Levothyroxine.
Gilteritinib Gilteritinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Gilteritinib.
Glasdegib Glasdegib The metabolism of Glasdegib can be decreased when combined with Levothyroxine.
Lorlatinib Lorlatinib The metabolism of Lorlatinib can be decreased when combined with Levothyroxine.
Larotrectinib Larotrectinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Larotrectinib.
Paclitaxel (with albumin) Injection Paclitaxel (with albumin) Injection The metabolism of Paclitaxel can be decreased when combined with Levothyroxine.
Erdafitinib Erdafitinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Erdafitinib.
Esomeprazole Injection Esomeprazole Injection Esomeprazole can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Entrectinib Entrectinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Entrectinib.
Pexidartinib Pexidartinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Pexidartinib.
Istradefylline Istradefylline The metabolism of Istradefylline can be decreased when combined with Levothyroxine.
Fedratinib Fedratinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Fedratinib.
Lefamulin Lefamulin Levothyroxine may increase the excretion rate of Lefamulin which could result in a lower serum level and potentially a reduction in efficacy.
Phenytoin Injection Phenytoin Injection The metabolism of Levothyroxine can be decreased when combined with Phenytoin.
Fosphenytoin Injection Fosphenytoin Injection The metabolism of Fosphenytoin can be decreased when combined with Levothyroxine.
Calcium Acetate Calcium Acetate The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Calcium acetate.
Bempedoic Acid Bempedoic Acid The excretion of Bempedoic acid can be decreased when combined with Levothyroxine.
Ozanimod Ozanimod The metabolism of Ozanimod can be decreased when combined with Levothyroxine.
Selumetinib Selumetinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Selumetinib.
Tucatinib Tucatinib The therapeutic efficacy of Tucatinib can be decreased when used in combination with Levothyroxine.
Selpercatinib Selpercatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Selpercatinib.
Capmatinib Capmatinib The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Capmatinib.
Belantamab Mafodotin-blmf Injection Belantamab Mafodotin-blmf Injection The excretion of Belantamab mafodotin can be decreased when combined with Levothyroxine.
Relugolix Relugolix The serum concentration of Relugolix can be decreased when it is combined with Levothyroxine.
Theophylline Theophylline Levothyroxine may increase the excretion rate of Theophylline which could result in a lower serum level and potentially a reduction in efficacy.
Indomethacin Indomethacin The metabolism of Levothyroxine can be decreased when combined with Indomethacin.
Naproxen Naproxen The metabolism of Naproxen can be decreased when combined with Levothyroxine.
Trazodone Trazodone The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Trazodone.
Sucralfate Sucralfate Sucralfate can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Sodium Bicarbonate Sodium Bicarbonate Sodium bicarbonate can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Floxuridine Floxuridine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Floxuridine.
Phenobarbital Phenobarbital The metabolism of Levothyroxine can be increased when combined with Phenobarbital.
Methotrexate Injection Methotrexate Injection The excretion of Methotrexate can be decreased when combined with Levothyroxine.
Primidone Primidone The metabolism of Levothyroxine can be increased when combined with Primidone.
Diethylpropion Diethylpropion The risk or severity of adverse effects can be increased when Diethylpropion is combined with Levothyroxine.
Diazepam Diazepam The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Diazepam.
Bromocriptine Bromocriptine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Bromocriptine.
Metaproterenol Metaproterenol The risk or severity of adverse effects can be increased when Orciprenaline is combined with Levothyroxine.
Dapsone Dapsone The metabolism of Dapsone can be decreased when combined with Levothyroxine.
Sulfadiazine Sulfadiazine The therapeutic efficacy of Sulfadiazine can be decreased when used in combination with Levothyroxine.
Methadone Methadone The therapeutic efficacy of Methadone can be decreased when used in combination with Levothyroxine.
Colestipol Colestipol Colestipol can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Maprotiline Maprotiline The risk or severity of adverse effects can be increased when Levothyroxine is combined with Maprotiline.
Ibuprofen Ibuprofen The metabolism of Ibuprofen can be decreased when combined with Levothyroxine.
Perphenazine Perphenazine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Perphenazine.
Phentermine Phentermine The risk or severity of adverse effects can be increased when Phentermine is combined with Levothyroxine.
Amoxapine Amoxapine The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Amoxapine.
Sulfasalazine Sulfasalazine The therapeutic efficacy of Levothyroxine can be increased when used in combination with Sulfasalazine.
Doxorubicin Doxorubicin The serum concentration of Doxorubicin can be decreased when it is combined with Levothyroxine.
Dactinomycin Dactinomycin The serum concentration of Dactinomycin can be decreased when it is combined with Levothyroxine.
Carbamazepine Carbamazepine The metabolism of Levothyroxine can be increased when combined with Carbamazepine.
Cimetidine Cimetidine Cimetidine can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Warfarin Warfarin The therapeutic efficacy of Levothyroxine can be increased when used in combination with Warfarin.
Loperamide Loperamide The metabolism of Loperamide can be decreased when combined with Levothyroxine.
Meclofenamate Meclofenamate The therapeutic efficacy of Meclofenamic acid can be increased when used in combination with Levothyroxine.
Nitrofurantoin Nitrofurantoin The therapeutic efficacy of Nitrofurantoin can be increased when used in combination with Levothyroxine.
Digoxin Digoxin Levothyroxine may increase the excretion rate of Digoxin which could result in a lower serum level and potentially a reduction in efficacy.
Chloroquine Chloroquine The metabolism of Chloroquine can be decreased when combined with Levothyroxine.
Quinine Quinine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Quinine.
Desipramine Desipramine The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Desipramine.
Amitriptyline Amitriptyline The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Amitriptyline.
Imipramine Imipramine The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Imipramine.
Probenecid Probenecid The metabolism of Levothyroxine can be decreased when combined with Probenecid.
Quinidine Quinidine The serum concentration of Levothyroxine can be decreased when it is combined with Quinidine.
Rifampin Rifampin The metabolism of Levothyroxine can be increased when combined with Rifampicin.
Disopyramide Disopyramide The therapeutic efficacy of Disopyramide can be decreased when used in combination with Levothyroxine.
Valproic Acid Valproic Acid The metabolism of Levothyroxine can be decreased when combined with Valproic acid.
Tamoxifen Tamoxifen The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Tamoxifen.
Chlorpropamide Chlorpropamide The therapeutic efficacy of Chlorpropamide can be decreased when used in combination with Levothyroxine.
Tolbutamide Tolbutamide The therapeutic efficacy of Tolbutamide can be decreased when used in combination with Levothyroxine.
Tolazamide Tolazamide The therapeutic efficacy of Tolazamide can be decreased when used in combination with Levothyroxine.
Niacin Niacin The therapeutic efficacy of Levothyroxine can be increased when used in combination with Niacin.
Dantrolene Dantrolene The therapeutic efficacy of Dantrolene can be increased when used in combination with Levothyroxine.
Danazol Danazol The therapeutic efficacy of Levothyroxine can be increased when used in combination with Danazol.
Propranolol (Cardiovascular) Propranolol (Cardiovascular) The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Propranolol.
Pseudoephedrine Pseudoephedrine The risk or severity of adverse effects can be increased when Pseudoephedrine is combined with Levothyroxine.
Nortriptyline Nortriptyline The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Nortriptyline.
Mercaptopurine Mercaptopurine Levothyroxine may increase the excretion rate of Mercaptopurine which could result in a lower serum level and potentially a reduction in efficacy.
Nadolol Nadolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Nadolol.
Cholestyramine Resin Cholestyramine Resin Cholestyramine can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Fluorouracil Injection Fluorouracil Injection The metabolism of Fluorouracil can be decreased when combined with Levothyroxine.
Iron Supplements Iron Supplements Iron can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Ketoconazole Ketoconazole The metabolism of Levothyroxine can be decreased when combined with Ketoconazole.
Vincristine Injection Vincristine Injection The serum concentration of Vincristine can be decreased when it is combined with Levothyroxine.
Isoxsuprine Isoxsuprine The risk or severity of adverse effects can be increased when Isoxsuprine is combined with Levothyroxine.
Vinblastine Vinblastine The serum concentration of Vinblastine can be decreased when it is combined with Levothyroxine.
Metoprolol Metoprolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Metoprolol.
Aspirin Aspirin The therapeutic efficacy of Levothyroxine can be increased when used in combination with Acetylsalicylic acid.
Diltiazem Diltiazem The metabolism of Diltiazem can be decreased when combined with Levothyroxine.
Timolol Timolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Timolol.
Verapamil Verapamil The metabolism of Verapamil can be decreased when combined with Levothyroxine.
Atenolol Atenolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Atenolol.
Pindolol Pindolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Pindolol.
Diflunisal Diflunisal The therapeutic efficacy of Levothyroxine can be increased when used in combination with Diflunisal.
Piroxicam Piroxicam The metabolism of Piroxicam can be decreased when combined with Levothyroxine.
Etoposide Etoposide The serum concentration of Etoposide can be decreased when it is combined with Levothyroxine.
Glyburide Glyburide The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Glyburide.
Glipizide Glipizide The therapeutic efficacy of Glipizide can be decreased when used in combination with Levothyroxine.
Pentoxifylline Pentoxifylline Levothyroxine may increase the excretion rate of Pentoxifylline which could result in a lower serum level and potentially a reduction in efficacy.
Pentamidine Injection Pentamidine Injection The therapeutic efficacy of Pentamidine can be decreased when used in combination with Levothyroxine.
Labetalol Labetalol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Labetalol.
Gemfibrozil Gemfibrozil The metabolism of Levothyroxine can be decreased when combined with Gemfibrozil.
Flurbiprofen Flurbiprofen The metabolism of Levothyroxine can be decreased when combined with Flurbiprofen.
Amiodarone Amiodarone The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Amiodarone.
Lovastatin Lovastatin The metabolism of Lovastatin can be decreased when combined with Levothyroxine.
Ciprofloxacin Ciprofloxacin Ciprofloxacin can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Mesalamine Mesalamine The therapeutic efficacy of Levothyroxine can be increased when used in combination with Mesalazine.
Diclofenac Diclofenac The metabolism of Diclofenac can be decreased when combined with Levothyroxine.
Fluoxetine Fluoxetine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Fluoxetine.
Pravastatin Pravastatin The excretion of Pravastatin can be decreased when combined with Levothyroxine.
Simvastatin Simvastatin The metabolism of Simvastatin can be decreased when combined with Levothyroxine.
Sotalol Sotalol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Sotalol.
Bisoprolol Bisoprolol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Bisoprolol.
Omeprazole Omeprazole Omeprazole can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Cisapride Cisapride The metabolism of Cisapride can be decreased when combined with Levothyroxine.
Fluvastatin Fluvastatin The metabolism of Fluvastatin can be decreased when combined with Levothyroxine.
Nizatidine Nizatidine Nizatidine can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Fluvoxamine Fluvoxamine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Fluvoxamine.
Nefazodone Nefazodone The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Nefazodone.
Lamotrigine Lamotrigine The metabolism of Levothyroxine can be increased when combined with Lamotrigine.
Lansoprazole Lansoprazole Lansoprazole can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Ifosfamide Injection Ifosfamide Injection The metabolism of Ifosfamide can be decreased when combined with Levothyroxine.
Pegaspargase Injection Pegaspargase Injection The therapeutic efficacy of Levothyroxine can be increased when used in combination with Pegaspargase.
Nicardipine Nicardipine The metabolism of Nicardipine can be decreased when combined with Levothyroxine.
Metformin Metformin The therapeutic efficacy of Metformin can be decreased when used in combination with Levothyroxine.
Acarbose Acarbose The therapeutic efficacy of Acarbose can be decreased when used in combination with Levothyroxine.
Glimepiride Glimepiride The therapeutic efficacy of Glimepiride can be decreased when used in combination with Levothyroxine.
Anastrozole Anastrozole The metabolism of Levothyroxine can be decreased when combined with Anastrozole.
Gemcitabine Injection Gemcitabine Injection The serum concentration of Gemcitabine can be decreased when it is combined with Levothyroxine.
Indinavir Indinavir The metabolism of Levothyroxine can be decreased when combined with Indinavir.
Ritonavir Ritonavir The metabolism of Levothyroxine can be increased when combined with Ritonavir.
Docetaxel Injection Docetaxel Injection The excretion of Docetaxel can be decreased when combined with Levothyroxine.
Clomipramine Clomipramine The risk or severity of Cardiac Arrhythmia and CNS stimulation can be increased when Levothyroxine is combined with Clomipramine.
Zafirlukast Zafirlukast The metabolism of Zafirlukast can be decreased when combined with Levothyroxine.
Mirtazapine Mirtazapine The risk or severity of adverse effects can be increased when Mirtazapine is combined with Levothyroxine.
Valsartan Valsartan The excretion of Valsartan can be decreased when combined with Levothyroxine.
Insulin Lispro Injection Insulin Lispro Injection The therapeutic efficacy of Insulin lispro can be decreased when used in combination with Levothyroxine.
Nelfinavir Nelfinavir The metabolism of Levothyroxine can be increased when combined with Nelfinavir.
Fexofenadine Fexofenadine The excretion of Fexofenadine can be decreased when combined with Levothyroxine.
Carvedilol Carvedilol The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Carvedilol.
Selegiline Selegiline The metabolism of Selegiline can be decreased when combined with Levothyroxine.
Sertraline Sertraline The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Sertraline.
Propafenone Propafenone The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Propafenone.
Raloxifene Raloxifene Raloxifene can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Irbesartan Irbesartan The metabolism of Irbesartan can be decreased when combined with Levothyroxine.
Paroxetine Paroxetine The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Paroxetine.
Citalopram Citalopram The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Citalopram.
Efavirenz Efavirenz The metabolism of Levothyroxine can be increased when combined with Efavirenz.
Pioglitazone Pioglitazone The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Pioglitazone.
Celecoxib Celecoxib The metabolism of Celecoxib can be decreased when combined with Levothyroxine.
Rosiglitazone Rosiglitazone The therapeutic efficacy of Rosiglitazone can be decreased when used in combination with Levothyroxine.
Aluminum Hydroxide Aluminum Hydroxide The serum concentration of Levothyroxine can be decreased when it is combined with Aluminum hydroxide.
Colesevelam Colesevelam The therapeutic efficacy of Levothyroxine can be decreased when used in combination with Colesevelam.
Balsalazide Balsalazide The therapeutic efficacy of Levothyroxine can be increased when used in combination with Balsalazide.
Nateglinide Nateglinide The therapeutic efficacy of Nateglinide can be decreased when used in combination with Levothyroxine.
Rabeprazole Rabeprazole Rabeprazole can cause a decrease in the absorption of Levothyroxine resulting in a reduced serum concentration and potentially a decrease in efficacy.
Terbinafine Terbinafine The metabolism of Terbinafine can be decreased when combined with Levothyroxine.

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