Drug interactions
Phenytoin + Pitolisant
Severity: Moderate
Phenytoin and Pitolisant: moderate 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
Phenytoin, a strong CYP3A4 inducer, roughly halves pitolisant exposure, which may lead to loss of efficacy in narcolepsy.
What this interaction means in plain words
Phenytoin and Pitolisant can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Phenytoin belongs to Central Nervous System; Pitolisant belongs to Central Nervous System.
Why it happens
CYP3A4 induction by phenytoin increases the metabolism of pitolisant.
What to do
Double the pitolisant dose gradually over 7 days according to labeling. Halve the dose again if phenytoin is stopped.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Pitolisant
- Alfuzosin + Pitolisant Major
- Amiodarone + Pitolisant Major
- Amisulpride + Pitolisant Major
- Anagrelide + Pitolisant Major
- Asenapine + Pitolisant Major
- Bupropion + Pitolisant Major
Frequently asked questions
Can I take Phenytoin with Pitolisant?
MediHelp rates the interaction as moderate. Phenytoin and Pitolisant can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenytoin, a strong CYP3A4 inducer, roughly halves pitolisant exposure, which may lead to loss of efficacy in narcolepsy.
How serious is the interaction between Phenytoin and Pitolisant?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Double the pitolisant dose gradually over 7 days according to labeling. Halve the dose again if phenytoin is stopped.
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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