Drug interactions
Clarithromycin + Efavirenz
Severity: Moderate
Clarithromycin and Efavirenz: moderate 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 clarithromycin metabolism, lowering levels of the parent drug and increasing the less active metabolite, and rash is more frequent. Both drugs can also affect QT, though the main concern is reduced clarithromycin efficacy.
What this interaction means in plain words
Clarithromycin and Efavirenz can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Clarithromycin belongs to Anti Bacterial; Efavirenz belongs to Anti Virals.
Why it happens
CYP3A4 induction by efavirenz reduces clarithromycin exposure, with possible additive QT effects.
What to do
Consider azithromycin as an alternative, particularly for MAC infection. Monitor for rash and ECG changes if combined.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Clarithromycin and Efavirenz, 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 7 days on the web. No card needed.
Other interactions of Clarithromycin
- Astemizole + Clarithromycin Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Cisapride + Clarithromycin Contraindicated
- Clarithromycin + Colchicine Contraindicated
- Clarithromycin + Conivaptan Contraindicated
- Clarithromycin + Dihydroergotamine 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 Clarithromycin with Efavirenz?
MediHelp rates the interaction as moderate. Clarithromycin and Efavirenz can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Efavirenz induces clarithromycin metabolism, lowering levels of the parent drug and increasing the less active metabolite, and rash is more frequent. Both drugs can also affect QT, though the main concern is reduced clarithromycin efficacy.
How serious is the interaction between Clarithromycin and Efavirenz?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Consider azithromycin as an alternative, particularly for MAC infection. Monitor for rash and ECG changes if combined.
What other medicines interact with Clarithromycin?
MediHelp also lists interactions of Clarithromycin with, for example, Astemizole, Avanafil, Cisapride. The full list is on the Clarithromycin 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.
