CriticalMacrolide antibiotic×Selective serotonin reuptake inhibitors (SSRIs)
Updated · Methodology
Mechanism
Clarithromycin is a macrolide, and its own SmPC puts concomitant drugs associated with QT prolongation among its contraindications. The escitalopram SmPC contraindicates any QT-prolonging drug alongside it: the ban is written broadly, and the classes in brackets are examples. Clarithromycin inhibits CYP3A4, a minor metabolic path for escitalopram, so a small rise in antidepressant levels comes on top of the additive QT.
Symptoms
QTc prolongation on ECG, palpitations, dizziness, syncope. The end point is polymorphic ventricular tachycardia of the torsade type progressing to ventricular fibrillation. The risk is higher with hypokalaemia, hypomagnesaemia, bradycardia, decompensated heart failure and in women.
Management
The pair sits in the escitalopram SmPC contraindications, so the question is which drug stays, not how far to cut the dose. Both labels carry the ban, so the antibiotic course is planned not to overlap with the antidepressant. H. pylori eradication and respiratory infections have macrolide-free regimens.
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: Lexapro (escitalopram) prescribing information (2023)– FDA label, Allergan, Inc., DailyMed setid 13bb8267-1cab-43e5-acae-55a4d957630a, revised 10/2023, sections 4, 5.2 and 7
- AEMPS: Ficha técnica de Cipralex 10 mg (escitalopram) (2026)– AEMPS CIMA, nregistro 65230, revisión 03/2026, secciones 4.3 y 4.5
- AEMPS: Ficha técnica de Klacid 500 mg (claritromicina) (2024)– AEMPS CIMA, nregistro 60515, revisión 10/2024, secciones 4.3 y 4.4