Methylergometrine is a semisynthetic ergot alkaloid and a derivative of ergonovine. It is also known as methylergonovine. Methylergometrine acts directly on the smooth muscle of the uterus and increases the tone, rate, and amplitude of rhythmic contractions through binding and the resultant antagonism of the dopamine D1 receptor. Thus, it induces a rapid and sustained tetanic uterotonic effect which shortens the third stage of labor and reduces blood loss. It is used for the prevention and control of postpartum and post-abortion hemorrhage. In general, the effects of all the ergot alkaloids appear to results from their actions as partial agonists or antagonists at adrenergic, dopaminergic, and tryptaminergic receptors. The spectrum of effects depends on the agent, dosage, species, tissue, and experimental or physiological conditions. All of the alkaloids of ergot significantly increase the motor activity of the uterus. After small doses contractions are increased in force or frequency, or both, but are followed by a normal degree of relaxation. As the dose is increased, contractions become more forceful and prolonged, resting tonus is markedly increased, and sustained contracture can result.

Methylergometrine Mechanism of Action Pathway References