Drug Interaction Report

MONITOR: Drugs such as beta-blockers, calcium channel blockers, and nitrates may influence myocardial function and blood flow. Their effects on imaging results have not been studied, but may theoretically lead to false negatives in the diagnosis of coronary artery disease.

MANAGEMENT: Clinicians should consider concomitant medications that may influence myocardial function and blood flow when assessing images.

GENERALLY AVOID: Grapefruit and grapefruit juice may significantly increase the plasma concentrations of orally administered ranolazine. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because ranolazine prolongs QT interval in a dose-dependent manner, high plasma levels of ranolazine may increase the risk of ventricular arrhythmias such as ventricular tachycardia, ventricular fibrillation, and torsade de pointes.

MANAGEMENT: Patients treated with ranolazine should avoid consumption of grapefruit juice and other grapefruit products if possible. Otherwise, the dosage of ranolazine should be limited to 500 mg twice a day.