Major
Established
描述
Azithromycin and ondansetron both prolong the cardiac QT interval; their combination substantially increases the risk of torsades de pointes.
机制
Both drugs are hERG channel blockers; additive reduction in IKr potassium current prolongs the QTc interval in a dose-dependent, additive fashion.
临床意义
FDA issued safety communications for both drugs individually; combined use has been associated with arrhythmia events in case reports.
处理措施
Avoid concurrent use; select alternative antiemetics or antibiotics; monitor ECG and correct hypokalemia and hypomagnesemia if combination is essential.