Efficacy and tolerability of naratriptan for short-term prevention of menstrually related migraine: data from two randomized, double-blind, placebo-controlled studies.

BACKGROUND: In a pilot study, naratriptan was significantly more effective than placebo in preventing menstrually related migraine (MRM) when given as 1 mg twice daily for 5 days beginning 2 days before the predicted onset of MRM for up to 4 menstrual cycles.

OBJECTIVE: To evaluate the efficacy and tolerability of naratriptan for short-term prevention of MRM in 2 large, identically designed, randomized, double-blind, placebo-controlled, parallel-group studies.

METHODS: MRM was defined as any migraine beginning during the perimenstrual period (PMP). By definition, the PMP consisted of Days -2, -1, 1, 2, 3, and 4, with Day 1 being the first day of menstrual flow. Adult women were eligible if they reported a history of MRM, had regular menstrual cycles, and could predict within 2 days both the onset of menstrual flow and MRM. The studies comprised a baseline phase and a treatment phase. During the baseline phase, patients prophylactically treated their first PMP after the screening visit with single-blind placebo. Patients who documented an MRM while receiving placebo were eligible for the treatment phase. During the treatment phase, patients were randomized to receive either naratriptan 1 mg twice daily or placebo beginning 3 days before the predicted onset of MRM for a total of 6 days for 4 PMPs or 6 months, whichever occurred sooner. The primary efficacy endpoint was the mean percentage of treated PMPs without MRM per patient. Secondary efficacy endpoints included the percentage of patients who were free of MRM during all treated PMPs, the median number of days with MRM over 4 PMPs, and patient satisfaction. Safety and tolerability measures included adverse events, standard clinical laboratory tests, and vital signs.

RESULTS: The intent-to-treat population was 287 in Study 1 (149 in the naratriptan group and 138 in the placebo group) and 346 in Study 2 (173 in each treatment group). Approximately 20% of randomized patients in each treatment group in Study 1 and 10% in each treatment group in Study 2 withdrew prematurely from the studies over the 4-month treatment period. The mean percentage of PMPs without MRM per patient was 38% and 34% among naratriptan-treated patients treating at least 1 PMP compared with 29% and 24% among placebo-treated patients in each respective study (P < .05 naratriptan vs placebo for both studies). Efficacy of naratriptan did not vary as a function of age, use of oral contraceptives, or use of migraine prophylaxis. More patients who had received naratriptan reported attacks posttreatment compared to patients who had received placebo. Among patients treating at least 1 PMP, the percentage of patients with no MRM in any treated PMP was significantly (P < .05) higher in the naratriptan group (11%; 19/173) than the placebo group (3%; 6 of 173) in Study 2. There were no differences in the percentages of patients with no MRM in any treated PMP in Study 1. The number of MRM days per patient across 4 PMPs was significantly lower in the naratriptan group than in the placebo group in both studies (median 5.0 days vs 6.5 days in Study 1 [P= .005] and 5.3 days vs 6.0 days in Study 2 [P= .018]). Significantly more patients receiving naratriptan were satisfied with the ability of naratriptan to control MRM either by preventing their occurrence or reducing their severity or duration compared with patients receiving placebo. No single drug-related adverse event was reported by more than 2% of patients in a treatment group in either study, and no serious drug-related adverse events were reported.

CONCLUSIONS: Naratriptan 1 mg twice daily for 6 days per month is effective and well tolerated when used for short-term prevention of MRM. More patients receiving naratriptan than placebo were satisfied with treatment. The observed increase in posttreatment attacks needs further study.