The pharmacology of ergometrine

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Abstract
Ergometrine produces the central excitation, with general sympathetic stimulation, previously described as an initial phase of the action of the more complex alkaloids of the ergotoxine group. It has, however, no more than a trace of the specific paralyzing action on motor sympathetic effects, characteristic of these other alkaloids. It causes cyanosis of the cock''s comb, but the effect is evanescent and has not led to gangrene in a course of injections which, with ergotoxine, produced an extensive gangrene of the comb. Like ergotoxine, it causes a rise of body temp. when given in toxic doses. It is, in general, less toxic than ergotoxine, and is more readily absorbed with oral administration. The actions of ergometrine on the arterial pressure vary with the conditions of anaesthesia, or of integrity of the brain. In the spinal cat it has a pressor action, but far less than that of the alkaloids of the ergotoxine group. The most characteristic action, and the only one produced by small doses, is the initiation of a long persistent rhythm of powerful contractions in a uterus normally quiescent, as in the early puerperium. On several organs, apart from the centrally excited sympathetic stimulation, ergometrine appears to have a peripheral action of sympathomimetic type. This, however, is much complicated by other types of action, and does not account for its specific action on the uterus.