OBJECTIVE: The study purpose was to determine the relationship between pain severity and sumatriptan and OTC medication use for migraine attack treatment. METHODS: This study was part of a larger 6-month, prospective, observational study evaluating migraine-related outcomes in migraineurs within a managed care organization (MCO). The MCO is a mixed staff and independent practice association model. Enrolled patients were those who received their first prescription for sumatriptan and had been a member of the MCO for at least six months. Pain severity was self-recorded by patients as mild, moderate, or severe when each dose of medication was taken during the attack. RESULTS: A total of 168 patients reported 1304 migraine attacks with an average of 1.3 attacks/member/month. Of the 1304 attacks, 32% were mild, 43% were moderate, and 25% were severe at the time the first migraine medication was taken. Sumatriptan was used in 82% of migraine attacks. Patients were more likely to use sumatriptan during severe migraine attacks (86%) than in mild attacks (79%) (p<0.05). Patients were more likely to use OTC medications during mild attacks (55%) than in severe attacks (20%) (p<0.05). Patients who took sumatriptan as the first medication during an attack took fewer medication doses (2.4) than in attacks where sumatriptan was used as a second or subsequent dose (4.7) (p<0.05). CONCLUSION: This observational study shows that migraineurs in managed care tend to use OTC medications for mild migraine attacks and sumatriptan for severe attacks. Additional studies should be performed to evaluate the clinical and cost outcomes of this effect and to develop migraine medication treatment protocols to encourage appropriate treatment and management of migraine.