Keep an eye on Closely (1)pentobarbital will minimize the extent or outcome of fentanyl intranasal by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Intently. Coadministration of fentanyl with CYP3A4 inducers could lead into a lessen in fentanyl plasma concentrations, deficiency of efficacy or, maybe, improvement of