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 .
Caffeine augments the oral and rectal absorption of ergotamine.
This and other properties of caffeine may be responsible for enhancing the therapeutic effects of ergotamine. Important contraindications exist to the use of ergotamine. Because ergotamine-induced gangrene may occur in patients with infection, sepsis is a definite contraindication. Also it should not be used in patients with vascular disease and diseases of the liver or kidney. Other contraindications must also be observed.