Drug interactions
Efavirenz + Ergonovine
Severity: Major
Efavirenz and Ergonovine: 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 is a CYP3A4 inducer and may lower ergonovine exposure, reducing its uterotonic effect. However, ergot alkaloids with CYP3A4 inhibitors are the main toxicity concern, and the combination is labeled as to avoid; efavirenz can also variably inhibit CYP3A4.
What this interaction means in plain words
Efavirenz and Ergonovine 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 alters CYP3A4-mediated metabolism of ergonovine; the net effect is unpredictable.
What to do
Avoid if possible and use an alternative uterotonic such as oxytocin. If used, monitor for reduced effect and for signs of ergotism such as vasospasm.
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 Ergonovine, 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
Frequently asked questions
Can I take Efavirenz with Ergonovine?
MediHelp rates the interaction as major. Efavirenz and Ergonovine 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 is a CYP3A4 inducer and may lower ergonovine exposure, reducing its uterotonic effect. However, ergot alkaloids with CYP3A4 inhibitors are the main toxicity concern, and the combination is labeled as to avoid; efavirenz can also variably inhibit CYP3A4.
How serious is the interaction between Efavirenz and Ergonovine?
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 and use an alternative uterotonic such as oxytocin. If used, monitor for reduced effect and for signs of ergotism such as vasospasm.
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.
