Drug interactions
Efavirenz + Fexinidazole
Severity: Major
Efavirenz and Fexinidazole: 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 may change exposure to fexinidazole's active metabolites, and fexinidazole may in turn lower efavirenz levels. Higher metabolite concentrations raise QT prolongation risk, while lower efavirenz levels risk virologic failure.
What this interaction means in plain words
Efavirenz and Fexinidazole 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.
Why it happens
Efavirenz modulates CYP enzymes involved in fexinidazole metabolism, and fexinidazole may induce CYP2B6 and lower efavirenz exposure.
What to do
Avoid concurrent use where possible. If required, obtain ECGs, correct electrolytes, and monitor HIV viral load.
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 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 Fexinidazole?
MediHelp rates the interaction as major. Efavirenz and Fexinidazole 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 may change exposure to fexinidazole's active metabolites, and fexinidazole may in turn lower efavirenz levels. Higher metabolite concentrations raise QT prolongation risk, while lower efavirenz levels risk virologic failure.
How serious is the interaction between Efavirenz and Fexinidazole?
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 concurrent use where possible. If required, obtain ECGs, correct electrolytes, and monitor HIV viral load.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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