butabarbital will lower the extent or effect of sulfamethoxazole by influencing hepatic enzyme CYP2C9/10 metabolism. Slight/Importance Not known.butabarbital will minimize the level or impact of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Keep an eye on.butabarbital will lower the extent or influence of eltrombop