What are ergots for treating migraines?

In the 1930s, researchers discovered that ergotamine—a drug derived from a rye fungus—could abort migraine attacks by constricting blood vessels, which led to the development of the drug dihydroergotamine (DHE). Today, doctors rarely prescribe ergot-based drugs because they constrict blood vessels throughout the body and therefore cause more side effects than newer medications. Ergots also take longer to work than newer drugs; however, their beneficial effects last longer, so users are less likely to suffer a headache recurrence.

Ergotamine and caffeine suppositories or injectable dihydroergotamine may be useful for severe migraine headaches because they're absorbed faster than ergots in traditional pill form. But the ergotamine suppository, the most widely prescribed agent, tends to cause nausea and vomiting.

Dihydroergotamine is less likely than ergotamine to lead to nausea and vomiting. It used to be available only by injection, which made it a less popular alternative to ergotamine. The nasal spray version, Migranal, although easy to administer, is much less effective than the injection or the ergotamine suppositories because the tissue lining the nose doesn't absorb medication as well.