zantac and Cardioquin Interactions

Interactions between zantac(ranitidine) and Cardioquin (quinidine)

quinidine and ranitidine (Moderate Drug-Drug)

MONITOR: Cimetidine may increase serum quinidine levels and the risk of toxicity. The mechanism may be related to decreased CYP450 hepatic metabolism or competitive inhibition of renal excretion. A case of ventricular bigeminy has been reported with ranitidine coadministration, even though it is not expected to inhibit CYP450. No data are available for other H2-antagonists.

MANAGEMENT: If patients require cimetidine or ranitidine during quinidine therapy, monitoring for clinical and laboratory evidence of quinidine toxicity is recommended. Patients should be advised to notify their physician if they experience tinnitus, hearing loss, visual disturbances, diarrhea, dizziness, weakness, headache, syncope, or rapid or irregular heartbeats.