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.