pentobarbital will reduce the level or impact of tramadol by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Monitor. Diminished AUC of tramadol along with the Lively metabolite (O-desmethyltramadol) when coadministered with sturdy CYP3A4 and CYP2B6 inducerspentobarbital will minimize the extent or effect of fentanyl transderma… Read More