One in 3 epilepsy patients have refractory seizures. This drug resistance is likely related to the over expression of multidrug resistance proteins (MDR). Progesterone is a known inhibitor of MDRs and the low level of this hormone during the menstrual cycle may exacerbate seizures, perhaps explaining catamenial epilepsy; i.e. seizures occurring during the menstrual cycle. Verapamil suppresses seizures in animal models of epilepsy perhaps by inhibiting MDRs and thus may help patients with refractory seizures. If the study shows improved seizure control, the results will help establish the role of MDRs in refractory epilepsy.