Wiktionary
methysergide
n. A prescription drug used for prophylaxis of migraine headaches.
Wikipedia
Methysergide
Methysergide (1- methyl-D- lysergic acid butanol amide or UML-491) is a prescription drug formerly used for prophylaxis of cluster headaches/ migraine headaches, but is no longer recommended due to retroperitoneal/retropulmonary fibrosis.