CriticalMacrolide antibiotic×Ergot alkaloid, 5-HT1B/1D and alpha-adrenoceptor agonist
Updated · Methodology
Mechanism
Clarithromycin inhibits CYP3A4. Ergotamine is metabolised exclusively by CYP3A4; concentration rises 10+ fold. Fatal ergotism: digital ischaemia, MI, stroke. FDA boxed warning.
Symptoms
Within 1–3 days: digital numbness, pallor, limb pain; in severe cases gangrene. Fatal cases reported.
Management
Combination contraindicated. For migraine in a clarithromycin patient – switch ergotamine to triptan after course completion, or use paracetamol for acute attack.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Ergomar (ergotamine) prescribing information, Section 4 (2008)– ; DailyMed setid a9582fdb-7ddd-4f69-aa7a-66247cdb8c92
- AEMPS: Ficha técnica: Claritromicina (nº registro 75638), sección 4.3 (2025)– AEMPS, CIMA, nº registro 75638, revisión 03/2025, sección 4.3