molecular entity ergometrine Ergometrine A monocarboxylic acid amide that is lysergamide in which one of the hydrogens attached to the amide nitrogen is substituted by a 1-hydroxypropan-2-yl group (S-configuration). An ergot alkaloid that has a particularly powerful action on the uterus, its maleate (and formerly tartrate) salt is used in the active management of the third stage of labour, and to prevent or treat postpartum of postabortal haemorrhage caused by uterine atony: by maintaining uterine contraction and tone, blood vessels in the uterine wall are compressed and blood flow reduced. N-[(2S)-1-hydroxypropan-2-yl]-6-methyl-9,10-didehydroergoline-8beta-carboxamide