May activate 5HT1 receptors in the dura mater. Ergotamine is effective in relieving migraine headaches despite its lack of sedative or analgesic properties. Ergotamine is effective in the vast majority of migraine episodes. Relief is often dramatic. Only occasionally are other types of headaches relieved.
Ergotamine is ineffective in the prophylaxis of migraine.
Temporal relationships . After parenteral injection of dihydroergotamine, the migraine headache can be expected to disappear within 15 minutes. Oral administration may require 5 hours to be effective. Failure may occur in severe attacks with oral dosing. Interactions with caffeine .