Drug interactions
Clarithromycin + Loperamide
Severity: Major
Clarithromycin and Loperamide: 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
Clarithromycin prolongs the QT interval and also inhibits CYP3A4 and P-glycoprotein, which raises loperamide exposure. Both effects increase the risk of cardiac toxicity and central opioid effects.
What this interaction means in plain words
Clarithromycin and Loperamide 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; Loperamide belongs to Gastrointestinal Tract.
Why it happens
Additive QT prolongation plus CYP3A4 and P-glycoprotein inhibition increasing loperamide levels.
What to do
Avoid the combination where possible and choose a non-macrolide antibiotic. If used, limit loperamide dose and monitor ECG.
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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Other interactions of Loperamide
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 Loperamide?
MediHelp rates the interaction as major. Clarithromycin and Loperamide 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 prolongs the QT interval and also inhibits CYP3A4 and P-glycoprotein, which raises loperamide exposure. Both effects increase the risk of cardiac toxicity and central opioid effects.
How serious is the interaction between Clarithromycin and Loperamide?
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 where possible and choose a non-macrolide antibiotic. If used, limit loperamide dose and monitor ECG.
What other medicines interact with Loperamide?
MediHelp also lists interactions of Loperamide with, for example, Amiodarone, Amisulpride, Anagrelide. The full list is on the Loperamide page.
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