CriticalSelective serotonin reuptake inhibitors (SSRIs)×Fourth-generation fluoroquinolone
Updated · Methodology
Mechanism
Moxifloxacin is named outright in both SSRI labels. Its own SmPC forbids concomitant use with other QT-prolonging drugs and quotes the measured QTc increase of about 6 ms. The escitalopram SmPC contraindicates any QT-prolonging drug alongside it: the ban is written broadly, and the classes in brackets are examples.
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. Moxifloxacin is the most cardiac of the fluoroquinolones, and respiratory infections have replacements outside that group. This pair is resolved on the antibiotic side.
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: Moxifloxacin tablet (Chartwell Rx, LLC) – Prescribing Information – QT prolongation warning (2016)– FDA Avelox label, Warnings and Precautions §5.7 – avoid with QT-prolonging drugs; DailyMed setid 656f582c-ecba-4ec8-9420-9562114d889b
- DailyMed: Escitalopram: FDA prescribing information, Drug Interactions section (DailyMed) (2024)
- 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 Moxifloxacino Sandoz 400 mg (2026)– AEMPS CIMA, nregistro 74573, revisión 03/2026, secciones 4.3 y 4.4