CriticalSSRI (selective serotonin reuptake inhibitor)×Macrolide antibiotic
Updated · Methodology
Mechanism
Clarithromycin is a macrolide, and its own SmPC puts concomitant drugs associated with QT prolongation among its contraindications. The citalopram SmPC lists ongoing treatment with any drug capable of prolonging the QT interval among its contraindications, with no exceptions. Clarithromycin inhibits CYP3A4, a minor metabolic path for citalopram, 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 citalopram 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: Clarithromycin tablet (Solaris Pharma Corporation) – Prescribing Information section 7 (2017)– ; DailyMed setid 4d42821d-ce7a-7d64-e063-6294a90a0875
- AEMPS: Ficha técnica de Seropram 30 mg (citalopram) (2024)– AEMPS CIMA, nregistro 63564, revisión 01/2024, secciones 4.2, 4.3 y 4.4
- AEMPS: Ficha técnica de Klacid 500 mg (claritromicina) (2024)– AEMPS CIMA, nregistro 60515, revisión 10/2024, secciones 4.3 y 4.4