Drug interactions
Isavuconazonium + Phenytoin
Severity: Contraindicated
Isavuconazonium 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 can sharply reduce isavuconazole concentrations, risking failure of treatment for invasive fungal infection.
What this interaction means in plain words
Isavuconazonium 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.
Isavuconazonium belongs to Anti Fungals; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4 metabolism of isavuconazole.
What to do
Avoid the combination; use an alternative antifungal or anticonvulsant. If antifungal therapy is critical, consider a non-inducing antiepileptic.
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 Isavuconazonium
- Amobarbital + Isavuconazonium Contraindicated
- Apalutamide + Isavuconazonium Contraindicated
- Carbamazepine + Isavuconazonium Contraindicated
- Cisapride + Isavuconazonium Contraindicated
- Efavirenz + Isavuconazonium Contraindicated
- Enzalutamide + Isavuconazonium Contraindicated
Frequently asked questions
Can I take Isavuconazonium with Phenytoin?
MediHelp rates the interaction as contraindicated. Isavuconazonium 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 can sharply reduce isavuconazole concentrations, risking failure of treatment for invasive fungal infection.
How serious is the interaction between Isavuconazonium 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: Avoid the combination; use an alternative antifungal or anticonvulsant. If antifungal therapy is critical, consider a non-inducing antiepileptic.
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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