pentobarbital will minimize the extent or influence of etoposide by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Monitor.pentobarbital will minimize the level or impact of tramadol by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Watch. Reduced AUC of tramadol and the Energetic metabolite (O-desmethyltra