Drug Interactions between clarithromycin and ibutilide

GENERALLY AVOID: Macrolide antibiotics including azithromycin, clarithromycin, and erythromycin have been associated with prolongation of the QT interval and infrequent cases of cardiac arrhythmia. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). Elderly patients may also be more susceptible to drug-associated effects on the QT interval.

MANAGEMENT: The use of macrolide antibiotics in patients receiving class IA or class III antiarrhythmic agents antiarrhythmic agents should generally be avoided unless benefits are anticipated to outweigh the risks. Caution and clinical monitoring are recommended if these agents are prescribed together, especially to patients with underlying risk factors. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitations, irregular heartbeat, shortness of breath, or syncope.