Ergotamine absorption and toxicity.

Adverse reactions to ergotamine were noted in 16 out of 41 studies in which therapeutic doses of the drug were given to normal, healthy volunteers. In 17 of the studies 0.25 mg ergotamine was given by injection, 6 i.v. and 11 i.m., in 20 studies 2 mg ergotamine was given by mouth, and 4 subjects received 2 mg ergotamine by suppository. Plasma and urinary ergotamine was measured by radio-immunoassay. Adverse reactions were significantly more frequent in subjects in whom plasma ergotamine exceeded 1.8 ng/ml. Pharmacokinetic data derived from the study are presented and their relevance to the therapeutic use of ergotamine are discussed.