ModerateMacrolides×Macrolide antibiotic
Updated · Methodology
Mechanism
Dual macrolide therapy – doubled QT effect and redundant antibacterial activity without clinical rationale.
Symptoms
QT prolongation on ECG. Dizziness, syncope, palpitations. Rarely: polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia, hypomagnesaemia, bradycardia, and ischaemic heart disease.
Management
The combination is not prescribed. Choose one macrolide: azithromycin for upper respiratory infections and chlamydia (short course); clarithromycin for H. pylori and atypical pneumonia. When choosing, mind the interaction profile (clarithromycin is a strong CYP3A4 inhibitor).
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: Zithromax (azithromycin) prescribing information (2013)– ; DailyMed setid db52b91e-79f7-4cc1-9564-f2eee8e31c45