Sumatriptan succinate (GR 43175) is a serotonin1 (5-HT1) receptor agonist, which is effective in the acute treatment of migraine headache. Target: 5-HT 1d receptor agonist Sumatriptan succinate is a serotonin1 (5-HT1) receptor agonist, which is effective in the acute treatment of migraine headache. Its antimigraine activity is believed to derive from selective vasoconstriction of cranial blood vessels which are dilated and distended during migraine headache and/or from inhibition of neurogenically mediated inflammation in the dura mater . For sumatriptan succinate 50 mg versus placebo the NNTs were 6.1, 7.5, and 4.0 for pain-free at two hours and headache relief at one and two hours, respectively. NNTs for sustained pain-free and sustained headache relief during the 24 hours postdose were 9.5 and 6.0, respectively . Difference in time-weighted (0-2.5 h) mean arterial pressure MAP (90% confidence interval) was 1.2 mmHg (-0.2, 2.7) between telcagepant and placebo, 4.0 mmHg (2.5, 5.5) between sumatriptan succinate and placebo, and 1.5 mmHg (0.0, 3.0) between telcagepant with sumatriptan succinate vs sumatriptan succinate alone. When coadministered with telcagepant, the AUC0-6h and C(max) of sumatriptan succinate were increased by 23% and 24%, respectively. The small MAP increases observed after coadministration could possibly be associated with the slight elevations in sumatriptan succinate levels . Clinical indications: Cluster headache; Migraine Toxicity: Symptoms of overdose include convulsions, tremor, paralysis, inactivity, ptosis, erythema of the extremities, abnormal respiration, cyanosis, ataxia, mydriasis, salivation, and lacrimation