Fifteen studies in 12 publications were included (3 studies were reported in one paper, and 2 in another).
Improvement 60 minutes after administration (12 studies; 2,186 sumatriptan and 1,280 placebo): the combined effect size was 1.09 (95% confidence interval, CI: 1.02, 1.16). The overall q-statistic was non significant, indicating that the individual effect sizes were generally consistent across the studies. Pain free 60 minutes after administration (6 studies): the combined effect size was 0.91 (95% CI: 0.81, 1.01). The test for heterogeneity was not significant.
Improvement 120 minutes after administration (9 studies; 1,642 sumatriptan and 836 placebo): the combined average effect size was 1.03 (95% CI: 0.93, 1.12). The test for heterogeneity was not significant.
Pain free 120 minutes after administration (6 studies): the combined average effect size was 0.95 (95% CI: 0.80, 1.09). The test for heterogeneity was not significant.
Second dose needed (6 studies): the combined average effect size was -0.94 (95% CI: -0.83, -1.04). The test for heterogeneity was not significant.
Need for rescue medication (10 studies): the combined average effect size was -0.82 (95% CI: -0.73, -0.90). The test for heterogeneity was not significant.
Adverse effects (8 studies): the adverse effects reported included injection size reaction (51%), nausea and vomiting (14%), and flushing (7%). The combined average effect size for at least one adverse effect was 0.73 (95% CI: 0.65, 0.82). The test for heterogeneity was not significant.