OBJECTIVE: To confirm the efficacy advantage of eletriptan 40 mg over sumatriptan 100 mg. Background.-Eletriptan 80 mg has demonstrated significantly greater efficacy when compared to both sumatriptan 50 mg and 100 mg in two studies. Eletriptan 40 mg demonstrated significantly greater efficacy than sumatriptan 100 mg in one previous trial. METHODS: Two thousand one hundred thirteen patients with a diagnosis of migraine according to International Headache Society criteria were randomized using a double-blind, double-dummy, parallel-group design, and treated for a single migraine attack with either eletriptan 40 mg, sumatriptan 100 mg, or placebo. The primary endpoint was 2-hour headache response. Secondary endpoints included headache response rates at 1 hour, pain-free rates, absence of associated symptoms, functional response at 1 and 2 hours, and sustained headache response. RESULTS: Headache response rates at 2 hours postdose were significantly higher for eletriptan 40 mg (67%) than for sumatriptan 100 mg (59%; P <.001) and placebo (26%; P <.0001). Eletriptan 40 mg consistently showed significant (P <.01) efficacy over sumatriptan 100 mg across secondary clinical outcomes, including 1-hour headache response; 2-hour pain-free response; absence of nausea, photophobia, and phonophobia; functional improvement; use of rescue medication; treatment acceptability; and sustained headache response (P <.05). Overall, treatment-related adverse events were low, nausea being the only adverse event with an incidence of 2% or higher (4.9% with eletriptan, 4.2% sumatriptan, 2.8% placebo). CONCLUSION: This trial confirmed that eletriptan 40 mg offers superior efficacy in treating migraine pain and associated symptoms and in restoring patient functioning when compared with sumatriptan 100 mg.