Moderate
Azithromycin × Sertraline
Macrolides×Selective serotonin reuptake inhibitors (SSRIs)
Mechanism
Additive QT prolongation (sertraline minimally prolongs QT at standard doses, azithromycin dose-dependently).
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 azithromycin courses (3–5 days) with sertraline ≤150 mg, the combination is acceptable. In cardiovascular disease: ECG before start or alternative antibiotics (doxycycline, a cephalosporin).