Drug interactions
Phenytoin + Sofosbuvir-velpatasvir-voxilaprevir
Severity: Contraindicated
Phenytoin and Sofosbuvir-velpatasvir-voxilaprevir: 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 induces CYP3A4, CYP2B6 and P-gp and is expected to substantially lower exposure to sofosbuvir, velpatasvir and voxilaprevir. This risks virologic failure. Labeling recommends against use together.
What this interaction means in plain words
Phenytoin and Sofosbuvir-velpatasvir-voxilaprevir 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; Sofosbuvir-velpatasvir-voxilaprevir belongs to Anti Virals.
Why it happens
Induction of CYP enzymes and P-glycoprotein by phenytoin reduces absorption and increases clearance of the antiviral components.
What to do
Do not coadminister; change to a non-inducing antiepileptic before starting HCV therapy.
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 Sofosbuvir-velpatasvir-voxilaprevir
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Phenobarbital + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Rifampin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Rifapentine + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Sofosbuvir-velpatasvir-voxilaprevir + St john's wort Contraindicated
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
Frequently asked questions
Can I take Phenytoin with Sofosbuvir-velpatasvir-voxilaprevir?
MediHelp rates the interaction as contraindicated. Phenytoin and Sofosbuvir-velpatasvir-voxilaprevir 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 induces CYP3A4, CYP2B6 and P-gp and is expected to substantially lower exposure to sofosbuvir, velpatasvir and voxilaprevir. This risks virologic failure. Labeling recommends against use together.
How serious is the interaction between Phenytoin and Sofosbuvir-velpatasvir-voxilaprevir?
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 coadminister; change to a non-inducing antiepileptic before starting HCV therapy.
What other medicines interact with Sofosbuvir-velpatasvir-voxilaprevir?
MediHelp also lists interactions of Sofosbuvir-velpatasvir-voxilaprevir with, for example, Fosphenytoin, Phenobarbital, Primidone. The full list is on the Sofosbuvir-velpatasvir-voxilaprevir page.
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