pentobarbital will reduce the extent or outcome of tamoxifen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Keep track of.pentobarbital will lower the extent or influence of norgestrel by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep an eye on Carefully. Moderate CYP3A4 inducers may decrease pro