Drug interactions
Phenytoin + Velpatasvir
Severity: Contraindicated
Phenytoin and Velpatasvir: contraindicated 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 is a potent enzyme and P-glycoprotein inducer that markedly lowers velpatasvir exposure. This can cause failure of hepatitis C therapy and selection of resistance. Labeling advises against coadministration with such inducers.
What this interaction means in plain words
Phenytoin and Velpatasvir are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Phenytoin belongs to Central Nervous System; Velpatasvir belongs to Anti Virals.
Why it happens
Phenytoin induces CYP3A4, CYP2B6, CYP2C8 and P-glycoprotein, increasing velpatasvir clearance.
What to do
Do not combine; use a non-inducing anticonvulsant such as levetiracetam during HCV treatment where feasible. Seek specialist advice before switching anticonvulsants.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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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 Velpatasvir
- Apalutamide + Velpatasvir Contraindicated
- Carbamazepine + Velpatasvir Contraindicated
- Bosentan + Velpatasvir Major
- Colchicine + Velpatasvir Major
- Efavirenz + Velpatasvir Major
- Enzalutamide + Velpatasvir Major
Frequently asked questions
Can I take Phenytoin with Velpatasvir?
MediHelp rates the interaction as contraindicated. Phenytoin and Velpatasvir are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Phenytoin is a potent enzyme and P-glycoprotein inducer that markedly lowers velpatasvir exposure. This can cause failure of hepatitis C therapy and selection of resistance. Labeling advises against coadministration with such inducers.
How serious is the interaction between Phenytoin and Velpatasvir?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not combine; use a non-inducing anticonvulsant such as levetiracetam during HCV treatment where feasible. Seek specialist advice before switching anticonvulsants.
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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