Drug interactions
Efavirenz + Voxelotor
Severity: Major
Efavirenz and Voxelotor: 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 lower voxelotor exposure and reduce its benefit in sickle cell disease. Voxelotor may in turn raise levels of sensitive CYP3A4 substrates.
What this interaction means in plain words
Efavirenz and Voxelotor 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; Voxelotor belongs to Miscellaneous.
Why it happens
Efavirenz induces CYP3A4, increasing voxelotor clearance; voxelotor weakly inhibits CYP3A4.
What to do
Avoid the combination; if unavoidable, increase the voxelotor dose as per labeling and monitor hemoglobin response. Consider a non-inducing antiretroviral.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Efavirenz and Voxelotor, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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
Other interactions of Voxelotor
- Amobarbital + Voxelotor Major
- Apalutamide + Voxelotor Major
- Carbamazepine + Voxelotor Major
- Cyclosporin + Voxelotor Major
- Enzalutamide + Voxelotor Major
- Ergotamine + Voxelotor Major
Frequently asked questions
Can I take Efavirenz with Voxelotor?
MediHelp rates the interaction as major. Efavirenz and Voxelotor 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 lower voxelotor exposure and reduce its benefit in sickle cell disease. Voxelotor may in turn raise levels of sensitive CYP3A4 substrates.
How serious is the interaction between Efavirenz and Voxelotor?
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 the combination; if unavoidable, increase the voxelotor dose as per labeling and monitor hemoglobin response. Consider a non-inducing antiretroviral.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
