pentobarbital will lessen the extent or impact of irinotecan by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/observe. pentobarbital will reduce the level or result of fostemsavir by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. pentobarbital will lower the level or impact of cinacalcet by impacting