Objective. -To investigate the efficacy and tolerability of almotriptan 12.5 mg in migraine patients who respond poorly to sumatriptan 50 mg. Background. -Poor response to sumatriptan therapy for acute migraine attacks has been documented in the literature, but few controlled trials have investigated the efficacy of an alternative triptan in this subgroup of patients. Methods. -Patients with an International Headache Society diagnosis of migraine who self-described as experiencing at least two unsatisfactory responses to sumatriptan treated their first migraine attack with open-label sumatriptan 50 mg. Patients who did not achieve 2-hour pain relief (improvement of headache from moderate/severe to mild/no headache) were then randomized to treat their second attack with almotriptan 12.5 mg or placebo under double-blind conditions. Results. -In the first attack, 221 of 302 participants (73%) did not achieve 2-hour pain relief with sumatriptan and were randomized to treatment of their second attack with almotriptan 12.5 mg or placebo. Of the 198 sumatriptan nonresponders who treated their second attack (99 almotriptan; 99 placebo), 70%had severe headache pain at baseline. Two-hour pain-relief rates were significantly higher with almotriptan compared to placebo (47.5%vs 23.2%; P < .001). A significant treatment effect for almotriptan was also seen in pain-free rates at 2 hours (33.3%vs 14.1%; P < .005) and sustained freedom from pain (20.9%vs 9.0%; P < .05). In the second attack, 7.1%of patients in the almotriptan group experienced adverse events compared to 5.1%in the placebo group (P=.77). Conclusions. -Almotriptan 12.5 mg is an effective and well-tolerated alternative for patients who respond poorly to sumatriptan 50 mg. A poor response to one triptan does not predict a poor response to other agents in that class. Objective-To investigate the efficacy and tolerability of almotriptan 12.5 mg in migraine patients who respond poorly to sumatriptan 50 mg. Background. -Poor response to sumatriptan therapy for acute migraine attacks has been documented in the literature, but few controlled trials have investigated the efficacy of an alternative triptan in this subgroup of patients. Methods - Patients with an International Headache Society diagnosis of migraine who self-described as experiencing at least two unsatisfactory responses to sumatriptan treated their first migraine attack with open-label sumatriptan 50 mg. Patients who did not achieve 2-hour pain relief (improvement of headache from moderate / severe to mild / no headache) were then randomized to treat their second attack with almotriptan 12.5 mg or placebo under double-blind conditions. Results. -In the first attack , 221 of 302 participants (73%) did not achieve 2-hour pain relief with sumatriptan and were randomized to treatment of their sec Ond attack with almotriptan 12.5 mg or placebo. Of the 198 sumatriptan nonresponders who treated their second attack (99 almotriptan; 99 placebo), 70% had severe headache pain at baseline. Two-hour pain-relief rates were significantly higher with almotriptan compared to placebo (47.5% vs 23.2%; P <.001). A significant treatment effect for almotriptan was also seen in pain-free rates at 2 hours (33.3% vs 14.1%; P <.005) and sustained freedom from pain % vs 9.0%; P <.05). In the second attack, 7.1% of patients in the almotriptan group experienced adverse events compared to 5.1% in the placebo group (P = .77). Conclusions. -Almotriptan 12.5 mg is an effective and well-tolerated alternative for patients who respond poorly to sumatriptan 50 mg. A poor response to one triptan does not predict a poor response to other agents in that class.