butabarbital will reduce the extent or impact of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Check Closely. The efficacy of hormonal contraceptives might be decreased.butabarbital will lessen the level or result of glecaprevir/pibrentasvir by impacting hepatic/in