May cause bleeding tendency w/ anticoagulants (eg, warfarin), antiplatelet drugs (eg, aspirin & ticlopidine), thrombolytic drugs (eg, urokinase & alteplase), prostaglandin E or its derivatives (eg, alprostadil & limaprost alfadex). Blood conc may be increased & effect may be potentiated w/ CYP3A4 & CYP2C9 inhibitors eg, cimetidine, diltiazem, erythromycin, ketoconazole, lansoprazole, itraconazole, miconazole, omeprazole, HIV-1 PIs). Caution w/ grapefruit juice. Potential additive hypotensive effect w/ reflex tachycardia w/ any other agent w/ potential to reduce BP or vasodilators eg, dihydropyridine Ca channel blockers.