Acetazolamide in women with catamenial epilepsy

Catamenial epilepsy is a condition characterized by an increase in seizures during particular phases of the menstrual cycle. The incidence of catamenial epilepsy varies widely, partly because of a lack of a universally adopted definition. Specific treatment options for these patients are limited. The use of acetazolamide (AZ) has been based largely on anecdotal reports demonstrating efficacy in small or poorly characterized populations. The purpose of this study was to analyze retrospectively the efficacy, safety profile, and tolerability of AZ in women with catamenial epilepsy.

Women with catamenial epilepsy identified from 1990 through 1999 were invited to participate in a retrospective telephone questionnaire addressing the relationship of seizures and the menstrual cycle and the use, efficacy, and adverse effects of AZ. Seizure outcome was classified as: seizure free (SF), significantly improved (SI), or not significantly improved (NSI). Responses to AZ were compared in women with different types of epilepsy and comparing continuous versus intermittent dosing using Fisher's exact tests.

Twenty women were identified who had received or were currently taking AZ. The drug was given continuously in 55% and intermittently in 45% of patients. A > or =50% decrease in the seizure frequency was reported by 40% of subjects. Response rates were similar in generalized and focal epilepsy and in temporal and extratemporal epilepsy. There was no significant difference in effectiveness comparing continuous with intermittent dosing. A loss of efficacy over 6-24 months was reported by 15% of women.

Despite our small sample and retrospective design, AZ appears to demonstrate efficacy for catamenial epilepsy.