Six double-blind randomised controlled trials (1,999 participants) were included in the review; one of these had a crossover design (506 participants). Four trials scored 5 out of 5 on quality. Methodological limitations for the other two trials related to lack of reporting for randomisation methods and blinding. No studies were rated as having a high risk of bias.
Compared with placebo, the proportion of patients free from menstrual migraine was statistically significantly increased among those taking frovatriptan in doses of 2.5mg once daily (RR 1.48, 95% CI 1.27 to 1.72; two trials; Ι²=0%) and 2.5mg twice daily (RR 1.82, 95% CI 1.58 to 2.09; two trials; Ι²=0%). The NNTB for the comparison involving the 2.5mg once daily regimen was 7.22 (95% CI 5.25 to 11.54). The NNTB for the comparison involving the 2.5mg twice daily regimen was 3.90 (95% CI 3.23 to 4.93).
A similar result was shown with the use of naratriptan in a dose of 1mg twice daily (RR 1.48, 95% 1.20 to 1.83; three trials; Ι²=14.5%). This comparison resulted in a NNTB of 7.98 (95% CI 5.24 to 16.71). One trial compared naratriptan 2.5mg twice daily with placebo and found no statistically significant differences in overall menstrual migraine rates or number of menstrual migraine days between the groups.
One trial (244 participants) compared zolmitriptan (2.5mg twice daily or three times daily) with placebo and found that both regimens had superior efficacy to placebo as demonstrated by a 50% or more reduction in the frequency of menstrual migraines and the mean number of breakthrough migraines per menstrual cycle. In the comparisons with placebo, the NNTB for the proportion of patients free from menstrual migraine per menstrual cycle was 4.98 (95% CI 3.26 to 10.57) for the 2.5mg twice daily regimen and 2.52 (95% CI 1.95 to 3.58) for the 2.5mg three times daily regimen.
Further results were reported fully in the paper.