Clinical and experimental effects of sumatriptan in humans.

Recent reviews on the mode of action of the anti-migraine drug sumatriptan arrived at contrasting conclusions. Whereas some reviewers concluded that vasoconstriction is the most important action, others suggest that neuronal inhibition is essential. Both views were based predominantly on animal or in vitro experiments. In this comment, Michel Ferrari and Pramod Saxena review the experimental effects of sumatriptan in humans and discuss the clinical validity of both theories. In addition, they examine the initial efficacy of treatment and the mechanism of recurrence of headache within 24 hours, which is the most important drawback of sumatriptan in clinical practice, next to its possible cardiac side effects.