Sage + Fosphenytoin Sodium
Fosphenytoin Sodium brand name: Sesquient.
Fosphenytoin Sodium falls into 4 drug categories that Sage can interact with; the most serious is rated moderate. Theoretically, taking sage might increase the sedative and adverse effects of CNS depressants.
Read the full interaction reportSage and Fosphenytoin Sodium
These two interact in 4 distinct ways. Each one is explained separately below.
Why Are There 4 Interactions?
Sage interacts with whole categories of medication. Fosphenytoin Sodium falls into 4 of those categories, so it can interact with Sage in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).
CNS DEPRESSANTS
1 of 4Why this applies to Fosphenytoin Sodium
Fosphenytoin Sodium falls under CNS DEPRESSANTS — the group Sage interacts with.
Some constituents of sage have CNS depressant activity.
Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
Fosphenytoin (Sesquient) is a hospital medicine that your body quickly turns into phenytoin, a seizure medication. It can already make people feel drowsy, dizzy, or unsteady on their feet. The concern here is simple: some natural compounds in sage may have a mild calming, sedating effect of their own. If they stack on top of fosphenytoin, you could in theory feel more sleepy or off-balance than usual.
I'll be honest, this warning is mostly theoretical and comes from lab studies, not real patient reports. Sprinkling sage on your dinner is very unlikely to matter. Concentrated sage extracts or sage essential oil are where I'd be more cautious. Since fosphenytoin is given in a controlled setting, just mention any sage supplements to your care team or pharmacist before adding them.
- Perry NS, Bollen C, Perry EK, Ballard C. Salvia for dementia therapy: review of pharmacological activity and pilot tolerability clinical trial. Pharmacol Biochem Behav 2003;75:651-9.. PubMed
CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES
2 of 4Fosphenytoin Sodium also falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES.
In vitro evidence suggests that aqueous extracts of sage can inhibit CYP2C19. So far, this interaction has not been reported in humans.
Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
Fosphenytoin is a seizure medicine that your body quickly turns into phenytoin. Phenytoin is partly cleared by a liver enzyme called CYP2C19. In test-tube studies, water-based sage extracts seemed to slow that enzyme down. If that happened in a person, phenytoin could build up a bit higher than expected.
That matters because phenytoin has a narrow safe range, so even small shifts can tip you into side effects like dizziness, drowsiness, slurred speech, unsteady walking, or jerky eye movements. Here is the reassuring part: this is only lab evidence and has never actually been reported in people, and normal cooking amounts of sage are very unlikely to cause trouble. Still, before using concentrated sage supplements, check with your pharmacist or doctor.
- Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42.. PubMed
CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES
3 of 4Fosphenytoin Sodium also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.
In vitro evidence suggests that aqueous extracts of sage can inhibit CYP2C9. So far, this interaction has not been reported in humans.
Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
Here's the quick picture with sage and fosphenytoin (Sesquient). Once it's in your body, fosphenytoin converts to phenytoin, which is cleared largely by a liver enzyme called CYP2C9. Lab studies suggest sage may slow that enzyme down. In theory, that could let phenytoin levels creep up, and since this is a narrow therapeutic index medicine, even a small bump can tip you into side effects like dizziness, unsteady walking, slurred speech, double vision, or drowsiness.
The honest part: this is only seen in test-tube studies, never reported in real patients, so it's far from certain. Cooking with sage is no concern. Concentrated sage extracts or oils are where caution makes sense. Before adding any sage supplement, please check with your pharmacist or doctor.
- Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42.. PubMed
ANTICONVULSANTS
4 of 4Fosphenytoin Sodium also falls under ANTICONVULSANTS.
Some species of sage can cause convulsions when consumed in large quantities.
Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
Fosphenytoin (Sesquient) is a hospital-given form of phenytoin, a seizure medicine where the dose has to stay in a fairly tight window. The concern here is mostly theoretical. Certain sage species contain thujone, a compound that in large or concentrated amounts may lower the seizure threshold and could work against what your anticonvulsant is trying to do. In plain terms, heavy use of sage extracts or sage essential oil might make seizures a little easier to trigger.
Keep in mind this comes from lab and animal data only, not strong human studies, and sage used as a normal cooking herb is very unlikely to cause a problem. It is the concentrated supplements and essential oil that deserve caution. Since seizure control is too important to gamble with, check with your doctor or pharmacist before using any sage product.
- Perry NB, Anderson RE, Brennan NJ, et al. Essential oils from dalmatian sage (Salvia officinalis l.): variations among individuals, plant parts, seasons, and sites. J Agric Food Chem 1999;47:2048-54..
What These Ratings Mean
Every interaction above is graded three ways — here’s the key to each label.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
- ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
- PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
- UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
- AHigh-quality meta-analysis (quantitative systematic review).
- BCase-control study.
- CConsensus.
- DAnecdotal evidence.
These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.
Sage Also Interacts With Other Medications
Sage has 1,295 moderate known drug interactions in our database — the Fosphenytoin Sodium one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Sage
We haven’t checked that one against Sage yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Sage. Pick one to open its full report.
See Every Supplement That Interacts With Fosphenytoin Sodium
This page covers Sage only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fosphenytoin Sodium page lists 212 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: 1,4-butanediol (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).
By severity: 14 major · 179 moderate · 19 minor.
From our pharmacist’s overview on the Fosphenytoin Sodium page
“Fosphenytoin sodium (Sesquient) converts to phenytoin in the body, and phenytoin is unforgiving about blood levels. A little too low invites seizures, a little too high brings toxicity.”
Reviewed by 2 · Jul 18, 2026
Taking Sage as Part of a Dietary Supplement Product? Check It for Interactions
We hold 718 real supplement products containing Sage, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sage. Your product may carry other ingredients that interact with Fosphenytoin Sodium too, on top of Sage — and those would not show on this page. Find your product and we’ll check every ingredient on its label:
Where Sage and Fosphenytoin Sodium Sit Against Everything Else
Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.
#246 of 1,452 supplements looked up here in the last 7 days
#741 of 2,830 medications looked up here in the last 7 days
Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.
About Sage
What is Sage?
- Sore throat and mouth irritation
- Digestive upset
- Excessive sweating
- Memory and thinking
- Menopause symptoms (hot flashes)
- General antioxidant support
Sage is a common kitchen herb that is generally safe in food amounts and is traditionally used for sore throats, digestion, sweating, and memory. Some early research is encouraging for sore throat and menopausal hot flashes, but most uses are not well proven. Concentrated extracts and the essential oil should be used carefully because high doses contain a compound called thujone, which can be harmful.
Other Drugs & Sage
Browse every other medication we’ve checked against Sage — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1,295 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Nifedipine ›
- Ibuprofen ›
- Diphenhydramine ›
- Hydrocortisone ›
- Insulin (rdna) ›
- Naproxen ›
- Doxycycline ›
- Erythromycin ›
- Estradiol ›
- Minocycline ›
- Propranolol ›
- Tetracycline ›
- Lidocaine ›
- Ranitidine ›
- Hydrochlorothiazide ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Flurazepam ›
- Glyburide ›
- Glycopyrrolate ›
- Insulin (pork) ›
- Triazolam ›
- Zopiclone ›
- Colchicine ›
- Fentanyl ›
- Flurbiprofen ›
- Oxybutynin ›
- Oxycodone ›
- Phenytoin ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Triamcinolone ›
- Apomorphine ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Diclofenac Potassium ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Hydralazine ›
- Indomethacin ›
- Insulin (human) ›
- Ipratropium ›
- Miconazole ›
- Morphine Sulfate ›
- Nitrazepam ›
- Procainamide ›
- Trimipramine ›
- Acetaminophen ›
Showing 60 of 1,295 moderate interactions — see all 1,295 on the Sage page.
No interaction 1,534 drugs checked — show the list
We also checked Sage against these medications and found no known interaction in our sources. Open any page to confirm.
- Levothyroxine ›
- Methylphenidate ›
- Aspirin ›
- Rosuvastatin ›
- Escitalopram ›
- Docusate ›
- Hydroxyurea ›
- Valacyclovir ›
- Sumatriptan ›
- Amoxicillin ›
- Isotretinoin ›
- Methotrexate ›
- Bupropion ›
- Bendamustine ›
- Acyclovir ›
- Azithromycin ›
- Methylene Blue ›
- Levothyroxine, Liothyronine ›
- Ciprofloxacin ›
- Amoxicillin, Clavulanate Potassium ›
- Cyclopentolate ›
- Cephalexin ›
- Roxithromycin ›
- Ezetimibe ›
- Acetylsalicylic Acid ›
- Dexmethylphenidate ›
- Levothyroxine Sodium ›
- Carbidopa, Levodopa ›
- Thyroid Hormone ›
- Pizotifen ›
- Daptomycin ›
- Pegunigalsidase Alfa-iwxj ›
- Mitomycin ›
- Levodopa ›
- Hexobarbitone ›
- Flutemetamol F-18 ›
- Magnesium Hydroxide (otc Drug) ›
- Bentoquatam ›
- Cefaclor ›
- Factor 7a ›
- Azelaic Acid ›
- Alglucosidase Alpha ›
- Hethylphenidate Hcl ›
- Salbutamol Sulfate ›
- Lenvatinib ›
- Tocainide ›
- Phenylephrine ›
- Hydroxychloroquine ›
- Ribavirin Aerosol ›
- Casanthranol, Docusate ›
- Rocuronium ›
- Vancomycin ›
- Triptorelin ›
- Isoniazid, Pyrazinamide, Rifampin ›
- Tenecteplase ›
- Dirithromycin ›
- Ropinirole ›
- Choline Magnesium Trisalicylate ›
- Birth Control Pills ›
- Ferric Derisomaltose ›
Showing the 60 most looked-up of 1,534 medications checked with no known interaction — see the full Sage list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Fosphenytoin Sodium Is Linked to Lower Levels of One Nutrient
Natural Medicines records Fosphenytoin Sodium as a medicine that can lower these. This is not an interaction with Sage — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Read the full Fosphenytoin Sodium nutrient depletion report ›
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Sage and Fosphenytoin Sodium Together: Common Questions
Can you take Sage with Fosphenytoin Sodium?
Why are there 4 interactions listed for Sage and Fosphenytoin Sodium?
How serious is the Sage and Fosphenytoin Sodium interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.