<prompt> Sumatriptan is a?5HT 1D antagonist5HT 1 agonist5HT 1D agonist5HT 1A antagonist  <response>: SUMATRIPTAN Selective agonist of the 5-HT1B1D receptor No interaction with adrenergic, dopaminergic and cholinergic receptors, GABA MOA: Blockade of 5-HT1D1B mediated constriction of dilated extracerebral blood vessel Constriction of the aeriovenous shunt of carotid aery Inhibition of release of 5-HT and inflammatory neuropeptides around the affected vessels - suppression of neurogenic inflammation Suppression of impulse transmission in the trigeminovascular system Kinetics: Poorly absorbed from GIT, bioavailability - 10 - 15 only Complete absorption after subcutaneous administration Metabolized by MAO-A and excreted in the urine, t12 is 2-3 Hrs Administration Doses: -The onset of an acute attack of migraine -Better tolerated than ergotamine -50 to 100 mg as initial dose and repeated after 24 Hrs if required -Should not be given is the first dose fails -SC dose - 12 mg 1 ml stat and repeated if required Adverse effects: Dose-related - Tightness of chest, feeling of heat, paresthesia of limbs, dizziness, and weakness sho lasting - common with SC route -Risk of MI and seizure and death Contraindications: IHD, epilepsy, hypeension, pregnancy, hepatic and renal impairment 