Responsiveness of non-IHS migraine and tension-type headache to sumatriptan.

In a long-term efficacy and safety study, 424 patients were treated with sumatriptan (6 mg sc) for 1,904 migraine attacks. The patients were diagnosed with migraine based on IHS criteria but individual migraine attacks treated in the study were physician diagnosed; not necessarily required to meet IHS criteria. A re-analysis of the treatment response to open label sumatriptan (6 mg sc) indicated that 43 patients had treated at least one migraine that fulfilled IHS criteria for tension-type headache. Analysis of this population revealed they treated 232 headaches. Of these headaches, 114 were classified per IHS criteria as migraine; 76 as tension-type; and 42 as non-IHS migraine (not classifiable as IHS migraine or IHS tension-type headache). Of the 114 migraines, a positive response to sumatriptan occurred in 109 (96%) cases; of the 76 tension-types, 73 responded to sumatriptan (97%); of the 42 non-IHS migraine, 40 (95%) responded to sumatriptan. An equivalent response to sumatriptan among three diagnostic groups of headache supports the concept of a common biologic mechanism involving 5HT1 receptors that spans a range of clinical presentations.