Drug interactions
Doravirine + Phenytoin
Severity: Contraindicated
Doravirine and Phenytoin: 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 markedly lowers doravirine concentrations, which may result in loss of virologic response and NNRTI resistance.
What this interaction means in plain words
Doravirine and Phenytoin 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.
Doravirine belongs to Anti Virals; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, which is the main metabolic pathway of doravirine.
What to do
Do not co-administer; use a non-inducing anticonvulsant. Doravirine labeling also advises against starting it soon after inducer discontinuation until induction wanes.
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
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
- Ensitrelvir + Phenytoin Contraindicated
Other interactions of Doravirine
- Amobarbital + Doravirine Contraindicated
- Apalutamide + Doravirine Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Doravirine + Efavirenz Contraindicated
- Doravirine + Enzalutamide Contraindicated
- Doravirine + Mitotane Contraindicated
Frequently asked questions
Can I take Doravirine with Phenytoin?
MediHelp rates the interaction as contraindicated. Doravirine and Phenytoin 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 markedly lowers doravirine concentrations, which may result in loss of virologic response and NNRTI resistance.
How serious is the interaction between Doravirine and Phenytoin?
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 co-administer; use a non-inducing anticonvulsant. Doravirine labeling also advises against starting it soon after inducer discontinuation until induction wanes.
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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