pentobarbital will reduce the level or effect of tramadol by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Observe. Reduced AUC of tramadol as well as the Lively metabolite (O-desmethyltramadol) when coadministered with robust CYP3A4 and CYP2B6 inducerspentobarbital will lessen the level or influence of tacrolimus by impacting