Efavirenz and Voriconazole: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Efavirenz and Voriconazole unless specifically directed by your doctor.
How Efavirenz interacts with Voriconazole
Efavirenz induces CYP3A4 and can markedly reduce voriconazole exposure, while voriconazole can increase efavirenz exposure through CYP inhibition. The net interaction can cause antifungal failure and efavirenz toxicity.
What you should do
Avoid standard coadministration unless using specialist-recommended dose adjustments. Monitor for antifungal efficacy and efavirenz adverse effects if no alternative exists.
Key facts
Severity
Major — avoid combination
Mechanism
Efavirenz induces CYP3A4 and can markedly reduce voriconazole exposure, while voriconazole can increase efavirenz exposu...
Action
Avoid standard coadministration unless using specialist-recommended dose adjustments. Monitor for antifungal efficacy an...
Frequently asked questions
Can I take Efavirenz and Voriconazole together?
No — this combination should generally be avoided. Avoid standard coadministration unless using specialist-recommended dose adjustments. Monitor for antifungal efficacy and efavirenz adverse effects if no alternative exists.
What is the severity of this interaction?
The interaction between Efavirenz and Voriconazole is classified as Major — avoid combination. Efavirenz induces CYP3A4 and can markedly reduce voriconazole exposure, while voriconazole can increase efavirenz exposure through CYP inhibition. The net interaction can cause antifungal failure and efavirenz toxicity.
What should I do if I'm prescribed both?
Avoid standard coadministration unless using specialist-recommended dose adjustments. Monitor for antifungal efficacy and efavirenz adverse effects if no alternative exists. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.