Butabarbital will lower the extent or outcome of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep an eye on Intently. The efficacy of hormonal contraceptives might be diminished. butabarbital will minimize the level or influence of sufentanil by influencing hepatic/intestinal enzyme CYP3A4 metabolis... https://donaldc136kwe2.wikicorrespondence.com/user