Sumatriptan: a new drug for vascular headache

The role of serotonin in the pathogenesis of migraine is discussed, and the chemistry, pharmacology, pharmacokinetics, efficacy, adverse effects, and dosage and administration of sumatriptan are reviewed. Sumatriptan, which is structurally related to the neurotransmitter serotonin, is a serotonin type-1-like-receptor agonist that has a selective but heterogeneous effect on the carotid arterial system. Sumatriptan has a rapid onset of action and a large volume of distribution. Its subcutaneous bioavailability approaches 100%, and its mean terminal half-life is two hours. Studies have shown that both subcutaneous sumatriptan and oral sumatriptan are superior to placebo in relieving migraine and cluster headaches. Studies comparing oral sumatriptan with either ergotamine tartrate plus caffeine (Cafergot) or aspirin plus metoclopramide indicated that sumatriptan relieved headache more quickly and effectively; however, the dosages of these other agents may have been suboptimal. Sumatriptan is generally well tolerated by patients, and most dose-related effects are mild and transient. The most common adverse effect is pain at the injection site. No drug interactions have been identified so far. Subcutaneous sumatriptan 6 mg and oral sumatriptan 100 mg seem to offer the best benefit-to-risk ratio, although dosage and administration information is limited. Subcutaneous and oral sumatriptan are effective in aborting moderate to severe migraine and cluster headaches and their associated symtpoms. However, more studies are necessary to compare sumatriptan's efficacy with that of other treatments before it can be recommended as first-line therapy for migraine.