Avoid use of strong CYP3A inhibitors (eg, ketoconazole, itraconazole, voriconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir & telithromycin) & potent CYP3A inducers (eg, rifampin, phenytoin, carbamazepine & phenobarb). Higher serum conc of simvastatin, lovastatin. Reduced effectiveness w/ maintenance dose aspirin >100 mg. Increased C
max & AUC w/ cyclosporine; potent P-gp inhibitors & moderate CYP3A4 inhibitors eg, verapamil, quinidine. Monitor digoxin levels. Delayed & decreased exposure w/ morphine. Concomitant use w/ medicinal products inducing bradycardia & altering haemostasis.