Study of Phenobarbital Inhibition of Catamenial Epilepsy

Inclusion Criteria: * Adult female patients seeking medical attention for seizures * Regular menstrual cycles * At least 2 seizures per month * Must be on at least one form of birth control other than abstinence * Must be on a stable anticonvulsant regimen of at least one and not exceeding three anticonvulsants, and not be using any perimenstrual seizure medications of hormone preparations * If taking benzodiazepines for therapeutic purposes, must be on a stable regular dose * Must be willing to take at least 400mcg of folic acid a day while in the study * Must be able to detect, count or record seizures Exclusion Criteria: * Can not be pregnant or trying to become pregnant * Can not have used hormonal birth control methods for at least 3 months prior to enrollment * Can not have an allergy to Phenobarbital * Can not have a history of non-epileptic seizures * Can not have a know liver dysfunction or history of chronic hepatitis * Can not have a history of neurological disorder or history of status epilepticus in the preceding year * Can not ahve a physical or psychiatric condition which in the PIs opinion could compromise her ability to participate