Pentobarbital will decrease the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. pentobarbital will decrease the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. pentobarbital will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous... https://johsocial.com/story10883422/un-imparziale-vista-pentobarbital-hond