Major
Probable
Descripción
Azithromycin and quetiapine both prolong the QT interval via hERG blockade; concurrent use significantly increases the risk of life-threatening arrhythmias.
Mecanismo
Additive hERG (IKr) potassium channel blockade prolongs ventricular repolarization; azithromycin also inhibits CYP3A4 modestly, potentially increasing quetiapine exposure.
Relevancia clínica
Multiple case reports and pharmacovigilance data document torsades de pointes with this combination.
Manejo clínico
Avoid combination; use alternative antibiotics (e.g., amoxicillin) when possible; if unavoidable, obtain ECG and correct electrolytes.