butabarbital, calcium/magnesium/potassium/sodium oxybates. Either boosts effects of one other by pharmacodynamic synergism. Contraindicated. Coadministration with Liquor or sedative hypnotics are contraindicated thanks to additive CNS depression.butabarbital will decrease the level or result of fosphenytoin by influencing hepatic enzyme CYP2C9/10 m