pentobarbital will lessen the level or result of mestranol by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Watch.pentobarbital will decrease the level or outcome of aprepitant by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Check.pentobarbital will lessen the level or effect of guanfacine by impacting h