Drug interactions
Clarithromycin + Fexinidazole
Severity: Major
Clarithromycin and Fexinidazole: major interaction.
Last updated Sources: US FDA label
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 prolong the QT interval, so combining them raises the risk of torsades de pointes. Clarithromycin may also reduce formation of active fexinidazole metabolites, potentially lowering efficacy, while fexinidazole may in turn affect clarithromycin exposure.
What this interaction means in plain words
Clarithromycin 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
Additive QT prolongation combined with CYP3A4-related changes in the metabolism of both agents.
What to do
Avoid the combination and choose a non-QT-prolonging antibiotic. If unavoidable, obtain a baseline ECG, correct potassium and magnesium, and monitor the ECG and treatment response.
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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References
Other interactions of Clarithromycin
- Astemizole + Clarithromycin Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Cisapride + Clarithromycin Contraindicated
- Clarithromycin + Colchicine Contraindicated
- Clarithromycin + Conivaptan Contraindicated
- Clarithromycin + Dihydroergotamine Contraindicated
Frequently asked questions
Can I take Clarithromycin with Fexinidazole?
MediHelp rates the interaction as major. Clarithromycin 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. Both drugs prolong the QT interval, so combining them raises the risk of torsades de pointes. Clarithromycin may also reduce formation of active fexinidazole metabolites, potentially lowering efficacy, while fexinidazole may in turn affect clarithromycin exposure.
How serious is the interaction between Clarithromycin 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 the combination and choose a non-QT-prolonging antibiotic. If unavoidable, obtain a baseline ECG, correct potassium and magnesium, and monitor the ECG and treatment response.
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.
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