<p>Ranolazine blocks QTc and prolongs the QTc interval in a dose-related manner. Clinical experience in an acute coronary syndrome population did not show an increased risk of proarrhythmia or sudden death.<br />
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Co-administration of ranolazine with digoxin increases the plasma concentrations of digoxin by approximately 1.5-fold and the dose of digoxin may have to be reduced accordingly. The dose of other P-gp substrates may have to be reduced as well when ranolazine Is co-admlnistered. Caution should be exercised when co-adminlstering ranolazine with P-gp inhibitors such as ritonavir or cydosporine.</p>