butabarbital will lessen the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Carefully. The efficacy of hormonal contraceptives can be minimized.Butabarbital, most commonly often called Butisol commercially, is undoubtedly an authorized Rou