An attack of migraine can be easily terminated by:

SPECIFIC ANTIMIGRAINE DRUGS Ergotamine: It is the most effective ergot alkaloid for migraine. Given early in attack, lower doses generally suffice, and relief is often dramatic. However, when pain has become severe-larger doses are needed and control may be achieved only after few hours. Oral/sublingual route is preferred. 1 mg is given at half hour intervals till relief is obtained or a total of 6 mg is given. Parenteral administration, though rapid in action is more hazardous. Ergotamine acts by constricting the dilated cranial vessels and/or by specific constriction of carotid A-V shunt channels. Ergotamine and DHE have also been shown to reduce neurogenic inflammation and leakage of plasma in duramater that occurs due to retrograde stimulation of periascular afferent nerves. These actions appear to be mediated through partial agonism at 5-HTID/IB receptors in and around cranial vessels. Reference: Essentials of Medical Pharmacology Eighth Edition KD TRIPATHI page no 193​