Is Adjunctive Progesterone Effective in Reducing Seizure Frequency in Patients with Intractable Catamenial Epilepsy? A Critically Appraised Topic

Background: Catamenial epilepsy refers to cyclic seizure exacerbation in relation to the menstrual cycle. Three distinct patterns have been described: C1-perimenstrual, C2-periovulatory, and C3-inadequate luteal. There is experimental and clinical evidence that gonadal steroid hormones affect neuronal excitability with estrogens being mainly proconvulsant and progesterone anticonvulsant. If reproductive steroids have a role in seizure occurrence, they may also have a role in treatment. Objective: The objective of this study was to critically assess current evidence regarding the efficacy of progesterone as adjunctive therapy in women with intractable catamenial epilepsy. Methods: The objective was addressed through the development of a structured critically appraised topic. This included a clinical scenario with a clinical question, literature search strategy, critical appraisal, results, evidence summary, commentary, and bottom line conclusions. Participants included consultant and resident neurologists, medical librarian, and content experts in the fields of epilepsy and gynecology. Results: A randomized, placebo-controlled clinical trial was selected for critical appraisal. This trial compared the efficacy of adjunctive cyclic natural progesterone therapy versus placebo for seizures in women with intractable partial epilepsy, stratified by catamenial and noncatamenial status. There was no significant difference in proportions of responders between progesterone and placebo in the catamenial and noncatamenial strata. Prespecified secondary analysis showed that the level of perimenstrual seizure exacerbation is a significant predictor of the responder rate for progesterone therapy. Conclusions: Cyclic natural progesterone is not superior to placebo in reducing seizure frequency in women with intractable partial epilepsy. Posthoc findings suggest that progesterone may benefit a subset of women with perimenstrually exacerbated seizures.