Drug interactions
Biotin + Phenytoin
Severity: Minor
Biotin and Phenytoin: 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
Long-term phenytoin use has been associated with lower biotin levels, possibly through reduced absorption or increased breakdown. Clinical deficiency is uncommon.
What this interaction means in plain words
Biotin and Phenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Biotin belongs to Gastrointestinal Tract; Phenytoin belongs to Central Nervous System.
Why it happens
Proposed reduced intestinal absorption and increased catabolism of biotin; the mechanism is not fully established.
What to do
Routine supplementation is not required. Consider biotin if signs of deficiency appear during long-term therapy.
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 Biotin
- Biotin + Levothyroxine Moderate
- Azithromycin + Biotin Minor
- Biotin + Carbamazepine Minor
- Biotin + Cefalexin Minor
- Biotin + Erythromycin base Minor
- Biotin + Erythromycin ethylsuccinate Minor
Frequently asked questions
Can I take Biotin with Phenytoin?
MediHelp rates the interaction as minor. Biotin and Phenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Long-term phenytoin use has been associated with lower biotin levels, possibly through reduced absorption or increased breakdown. Clinical deficiency is uncommon.
How serious is the interaction between Biotin and Phenytoin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Routine supplementation is not required. Consider biotin if signs of deficiency appear during long-term therapy.
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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