Serious cardiac events, including some that have been fatal, have occurred following the use of sumatriptan injection or tablets. Events reported have included coronary artery vasospasm, transient myocardial ischemia, myocardial infarction, ventricular tachycardia, and ventricular fibrillation.The most common side effects reported by at least 2% of patients in controlled trials of sumatriptan (25-, 50-, and 100-mg tablets) for migraine are atypical sensations (paresthesias and warm/cold sensations) reported by 4% in the placebo group and 5–6% in the sumatriptan groups, pain and other pressure sensations (including chest pain) reported by 4% in the placebo group and 6–8% in the sumatriptan groups, neurological events (vertigo) reported by less than 1% in the placebo group and less than 1% to 2% in the sumatriptan groups. Malaise/fatigue occurred in less than 1% of the placebo group and 2–3% of the sumatriptan groups. Sleep disturbance occurred in less than 1% in the placebo group to 2% in the sumatriptan group. Mechanism of action
Sumatriptan is molecularly similar to serotonin (5-HT), and is a 5-HT receptor (types 5-HT1D and 5-HT1B) agonist. Sumatriptans primary therapeutic effect is related in its inhibition of the release of Calcitonin gene-related peptide (CGRP), likely through its 5-HT1D/1B receptor-agonist action. This has been substantiated by the efficacy of more recently developed CGRP targeting drugs and antibodies developed for the preventive treatment of migraine. How agonism of the 5-HT1D/1B receptors inhibits CGRP release is not fully understood.
A nasal spray form of sumatriptan known as AVP-825 has been developed by Avanir and is generically available in some countries. Controversy
According to the American Headache Society, "Patients frequently state that they have difficulty accessing triptans prescribed to them." In the U.S. triptans cost from $12 to $120 each, and more that 80% of U.S. health  insurance plans limit place a limit on the amount of pills available to a patient per month, which has been called "arbitrary and unfair." References
External links
"Sumatriptan". Drug Information Portal. U.S. National Library of Medicine.