Drug interactions
Clarithromycin + Mefloquine
Severity: Major
Clarithromycin and Mefloquine: 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
Both drugs can prolong the QT interval, and clarithromycin may increase mefloquine exposure through CYP3A4 inhibition. Mefloquine has a very long half-life, so the risk of arrhythmia and neuropsychiatric toxicity can persist for weeks.
What this interaction means in plain words
Clarithromycin and Mefloquine 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.
Clarithromycin belongs to Anti Bacterial; Mefloquine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation plus CYP3A4 inhibition by clarithromycin reducing mefloquine clearance.
What to do
Avoid the combination and use a non-macrolide antibiotic. If unavoidable, obtain an ECG, correct electrolytes and monitor for cardiac and neuropsychiatric effects.
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 Clarithromycin and Mefloquine, 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 Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide Contraindicated
Frequently asked questions
Can I take Clarithromycin with Mefloquine?
MediHelp rates the interaction as major. Clarithromycin and Mefloquine 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. Both drugs can prolong the QT interval, and clarithromycin may increase mefloquine exposure through CYP3A4 inhibition. Mefloquine has a very long half-life, so the risk of arrhythmia and neuropsychiatric toxicity can persist for weeks.
How serious is the interaction between Clarithromycin and Mefloquine?
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 and use a non-macrolide antibiotic. If unavoidable, obtain an ECG, correct electrolytes and monitor for cardiac and neuropsychiatric effects.
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.
