Drug interactions
Efavirenz + Itraconazole
Severity: Major
Efavirenz and Itraconazole: major 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 induces CYP3A4 and can reduce itraconazole concentrations, risking antifungal failure. Itraconazole may raise efavirenz levels, and both can affect the QT interval.
What this interaction means in plain words
Efavirenz and Itraconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Efavirenz belongs to Anti Virals; Itraconazole belongs to Anti Fungals.
Why it happens
CYP3A4 induction of itraconazole by efavirenz, plus possible inhibition and additive QT effects.
What to do
Avoid if possible. If used, monitor itraconazole concentrations and clinical response, and check ECG when other QT risks exist.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole 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 Itraconazole?
MediHelp rates the interaction as major. Efavirenz and Itraconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Efavirenz induces CYP3A4 and can reduce itraconazole concentrations, risking antifungal failure. Itraconazole may raise efavirenz levels, and both can affect the QT interval.
How serious is the interaction between Efavirenz and Itraconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible. If used, monitor itraconazole concentrations and clinical response, and check ECG when other QT risks exist.
What other medicines interact with Itraconazole?
MediHelp also lists interactions of Itraconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Itraconazole page.
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