Moderate
Ciprofloxacin × Sertraline
Fluoroquinolone antibacterials×Selective serotonin reuptake inhibitors (SSRIs)
Mechanism
Both prolong QT. In low-risk patients the effect is clinically minor; risk rises with hypokalaemia, hypomagnesaemia, bradycardia, and concurrent QT-prolonging drugs.
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
For short ciprofloxacin courses (5–7 days) in young patients without cardiac disease, the combination is acceptable. In older patients, atrial fibrillation, hypokalaemia, or other QT-prolonging drugs: ECG before start, alternative antibiotics (cephalosporin, amoxicillin-clavulanate, doxycycline).
Sources
- Lexicomp: Lexicomp Drug Interactions (2024)– Wolters Kluwer Clinical Drug Information, Inc. Lexi-Interact Online, 2024
- FDA: FDA Drug Safety Communication: FDA updates warnings for oral and injectable fluoroquinolone antibiotics due to disabling side effects (2016)– FDA Drug Safety Communication, July 26, 2016