pentobarbital will reduce the level or effect of parecoxib by influencing hepatic enzyme CYP2C9/10 metabolism. Use Warning/Keep track of.pentobarbital will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep an eye on Closely. Average CYP3A4 inducers might decrease progestin conce