Carbetocin

Carbetocin (INN, BAN) (brand names Duratocin, Pabal, Lonactene, Depotocin, Comoton, Decomoton), or 1-butanoic acid-2-(O-methy-L-tyrosine)-1-carbaoxytocin, is an oxytocic used in obstetrics to control postpartum hemorrhage and bleeding after giving birth, particularly following Cesarean section. It is an eight amino acid long analogue of oxytocin (a nonapeptide) and has a similar mechanism of action. Carbetocin is an agonist at peripherally expressed oxytocin receptors. It is manufactured by Ferring Pharmaceuticals and is available in Canada and the United Kingdom and many other countries throughout the world, but not in the United States. Carbetocin works as an oxytocic, antihemorrhagic and uterotonic drug in the peripheral nervous system. The most common causes of postpartum hemorrhage are lack of tone in the uterus from overstretching or the use of an anesthetic. Carbetocin has been approved for use immediately following an elective Cesarean section when a local or spinal anesthesia has been administered. Since the uterus cannot contract on its own following incision during a Cesarean section, exogenous administration of oxytocin or an analog is necessary to restore uterine tone and prevent hemorrhage. Safety of carbetocin following vaginal births and emergency Cesarean sections has not been established, though studies have suggested efficacy following vaginal births to that following Cesarean sections. Some studies have shown that a 10-70 ug dose following vaginal delivery caused contractions and no adverse side effects. Carbetocin has also been shown to increase uterine involution (the return of the uterus to its contracted state after the birth of the baby) in humans, horses and cows. In 2018, heat-stable carbetocin, a formulation that does not require strict refrigeration, was found to be as good as oxytocin for reduction of postpartum hemorrhage after vaginal delivery. It is hoped that this will make oxytocic hemorrhage control more widely available and less expensive, which will be particularly useful in regions of developing countries where the cold chain (in drug transport and storage) is unreliable because of power outages or equipment problems. Carbetocin has also been shown to stimulate milk letdown through its action on the oxytocin receptors on the myoepithelial cells and there was not a significant amount of carbetocin in breastmilk.