Drug interactions
Efavirenz + Isavuconazole
Severity: Contraindicated
Efavirenz and Isavuconazole: 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
Efavirenz is a moderate CYP3A4 inducer and may lower isavuconazole exposure, compromising antifungal efficacy. Isavuconazole could also alter efavirenz concentrations.
What this interaction means in plain words
Efavirenz and Isavuconazole 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.
Efavirenz belongs to Anti Virals; Isavuconazole belongs to Anti Fungals.
Why it happens
Efavirenz induces CYP3A4/5, accelerating isavuconazole metabolism.
What to do
Avoid coadministration and use an alternative antiretroviral such as an integrase inhibitor-based regimen if feasible. If combined, monitor isavuconazole levels and clinical response.
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 Isavuconazole
- Carbamazepine + Isavuconazole Contraindicated
- Etravirine + Isavuconazole Contraindicated
- Isavuconazole + Ketoconazole Contraindicated
- Isavuconazole + Phenobarbitone Contraindicated
- Isavuconazole + Phenytoin Contraindicated
- Isavuconazole + Rifampicin Contraindicated
Other interactions of Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Efavirenz with Isavuconazole?
MediHelp rates the interaction as contraindicated. Efavirenz and Isavuconazole 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. Efavirenz is a moderate CYP3A4 inducer and may lower isavuconazole exposure, compromising antifungal efficacy. Isavuconazole could also alter efavirenz concentrations.
How serious is the interaction between Efavirenz and Isavuconazole?
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 coadministration and use an alternative antiretroviral such as an integrase inhibitor-based regimen if feasible. If combined, monitor isavuconazole levels and clinical response.
What other medicines interact with Isavuconazole?
MediHelp also lists interactions of Isavuconazole with, for example, Carbamazepine, Etravirine, Ketoconazole. The full list is on the Isavuconazole page.
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