CriticalSSRI (selective serotonin reuptake inhibitor)×Macrolide antibiotic
Updated · Methodology
Mechanism
Intravenous erythromycin is named outright in both SSRI labels, and its own SmPC forbids use in patients with a history of QT prolongation or with hypokalaemia and hypomagnesaemia. The citalopram SmPC lists ongoing treatment with any drug capable of prolonging the QT interval among its contraindications, with no exceptions.
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. The SSRI labels name the intravenous form, but oral erythromycin works through the same hERG blockade, and the dronedarone label, for one, bans the oral macrolide. The antibiotic is picked outside this group.
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: Erythrocin (erythromycin) prescribing information – QT prolongation, CYP3A4 inhibition (2017)– FDA Erythrocin label, Warnings §5.2; DailyMed setid a96c405f-bd70-4bb4-719e-ac6a79dcc213
- 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 Pantomicina 1 g (eritromicina) (2025)– AEMPS CIMA, nregistro 55771, revisión 09/2025, secciones 4.3 y 4.4