Drug interactions
Phenytoin + Tecovirimat
Severity: Minor
Phenytoin and Tecovirimat: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Tecovirimat may slightly raise phenytoin concentrations. The effect is probably small, but phenytoin has a narrow therapeutic index.
What this interaction means in plain words
Phenytoin and Tecovirimat have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Phenytoin belongs to Central Nervous System; Tecovirimat belongs to Miscellaneous.
Why it happens
Tecovirimat weakly inhibits CYP2C19 (and CYP2C8), reducing phenytoin metabolism.
What to do
Monitor for phenytoin toxicity and check levels if symptoms occur during the short tecovirimat course.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Tecovirimat
- Bosentan + Tecovirimat Moderate
- Cyclosporin + Tecovirimat Moderate
- Darunavir + Tecovirimat Moderate
- Ethinyl estradiol-drospirenone + Tecovirimat Moderate
- Ethinyl estradiol-levonorgestrel + Tecovirimat Moderate
- Glimepiride-pioglitazone + Tecovirimat Moderate
Frequently asked questions
Can I take Phenytoin with Tecovirimat?
MediHelp rates the interaction as minor. Phenytoin and Tecovirimat have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Tecovirimat may slightly raise phenytoin concentrations. The effect is probably small, but phenytoin has a narrow therapeutic index.
How serious is the interaction between Phenytoin and Tecovirimat?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for phenytoin toxicity and check levels if symptoms occur during the short tecovirimat course.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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