Treatment of nonresponders to oral sumatriptan with zolmitriptan and rizatriptan: a comparative open trial.

In order to study the effect of zolmitriptan and rizatriptan in oral sumatriptan nonresponders (defined as lack of response in three or more of five attacks), 56 patients were studied in an open trial in a crossover fashion. Both zolmitriptan, 5 mg, and rizatriptan, 10 mg, were effective in the majority of sumatriptan nonresponders. The response to rizatriptan, 10 mg, appeared to be better than to zolmitriptan, 5 mg. Approximately 19% of sumatriptan nonresponders remained nonresponders to both zolmitriptan and rizatriptan.