Ergot derivatives have a variety of different uses, including treating migraines, reducing bleeding after childbirth, and improving mental decline caused by dementia. They typically work by constricting blood vessels to reduce blood flow. Ergot derivatives come in different forms, including oral pills, a nasal spray, and injectable solutions. Examples include methylergonovine (Methergine), dihydroergotamine mesylate (D.H.E. 45, Migranal), and ergoloid mesylates.