pentobarbital decreases levels of vandetanib by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Steer clear of coadministration with powerful CYP3A4 inducers; these drugs lower publicity to vandetanib by as many as 40%.pentobarbital will lower the extent or influence of dasatinib by influencing hepatic/intestinal enzyme CYP3