Data from seven randomized, placebo-controlled, double-blind phase III clinical trials were analysed to further evaluate the efficacy of rizatriptan 10 mg (n = 2068) in comparison with placebo (n = 1260) and rizatriptan 5 mg (n = 1486) for the acute treatment of a migraine attack. Migraine was diagnosed according to International Headache Society criteria. Headache severity, associated migraine symptoms and functional disability were measured immediately before dosing and at 0.5, 1, 1.5 and 2 h. Headache recurrence (return of moderate or severe headache after an initial response) was also recorded. In addition to conventional pain relief (reduction of moderate or severe headache to mild or none) and pain free measures, the analysis looked at the elimination of associated migraine symptoms and disability in patients who had symptoms or disability at baseline. Maintenance of pain relief or pain-free status over 24 h was also analysed. At 2 h, rizatriptan 10 mg was significantly more effective than placebo for pain relief (71% vs. 38%, P < 0.001), and for elimination of pain, nausea, photophobia, phonophobia and functional disability. The benefit was maintained over 24 h; 37% of patients on rizatriptan 10 mg had sustained pain relief vs. 18% for placebo (P < 0.001). Rizatriptan 10 mg was also more effective than rizatriptan 5 mg, with a significant superiority at 2 h on all measures except for elimination of nausea. The benefit was maintained over 24 h; 38% of patients on rizatriptan 10 mg had sustained pain relief vs. 32% for rizatriptan 5 mg (P = 0.001).

CNS effects of sumatriptan and rizatriptanDear sir In their recent article, van der Post et al. (1) reported results from a study in which rizatriptan 10 mg and sumatriptan 100 mg were found to have minimal CNS effects, compared with temazepam 20 mg, on a battery of psychometric tests administered to 17 healthy women. Rizatriptan produced slightly greater impairment than sumatriptan, and the authors suggested that rizatriptan effects may have been underestimated because of encapsulation. The clinical relevance of these small differences between rizatriptan and sumatriptan in healthy women is unclear. To investigate this issue, we retrospectively analysed adverse event data from a large randomized, double-blind, placebo-controlled study which directly compared rizatriptan 10 mg with sumatriptan 100 mg for the treatment of a migraine attack (2). Supplies of rizatriptan and sumatriptan were not encapsulated. We looked at the percentages of migraine patients with any CNS adverse event, or with specific CNS adverse events of dizziness and drowsiness (the 2 most common CNS adverse events following triptan use). The results are shown in Table 1. There was no evidence that rizatriptan resulted in more CNS adverse events than sumatriptan. In fact, a slightly higher percentage of patients taking sumatriptan reported any CNS adverse event compared with patients taking rizatriptan. Both rizatriptan and sumatriptan were associated with an increase in CNS adverse events compared with placebo, but most events were of mild or moderate severity and were short-lasting. A study which directly compared rizatriptan 10 mg with the lower, 50-mg, dose of sumatriptan also found similar percentages of patients with CNS adverse events in the active treatment groups (3). These results suggest that, clinically, rizatriptan and sumatriptan have similar CNS effects.