Oxytocin (medication)

Synthetic oxytocin, sold under the brand name Pitocin among others, is a medication made from the peptide oxytocin. As a medication, it is used to cause contraction of the uterus to start labor, increase the speed of labor, and to stop bleeding following delivery. For this purpose, it is given by injection either into a muscle or into a vein. Oxytocin is also available in intranasal spray form for psychiatric, endocrine and weight management use as a supplement. Intranasal oxytocin works on a different pathway than injected oxytocin, primarily along the olfactory nerve crossing the brain blood barrier to the olfactory lobe in the brain, where dense magnocellular oxytocin neurons receive the dose application. The use of synthetic oxytocin as an injectable medication for inducing childbirth can result in excessive contraction of the uterus that can risk the health of the baby. Common side effects in the mother include nausea and a slow heart rate. Serious side effects include rupture of the uterus and with excessive dose, water intoxication. Allergic reactions including anaphylaxis may also occur. The natural occurrence of oxytocin was discovered in 1906. It is on the World Health Organization's List of Essential Medicines. An intravenous infusion of oxytocin is used to induce labor and to support labor in case of slow childbirth if the oxytocin challenge test fails. Whether a high dose is better than a standard dose for labor induction is unclear. It has largely replaced ergometrine as the principal agent to increase uterine tone in acute postpartum hemorrhage. Oxytocin is also used in veterinary medicine to facilitate birth and to stimulate milk release. The tocolytic agent atosiban (Tractocile) acts as an antagonist of oxytocin receptors. It is registered in many countries for use in suppressing premature labor between 24 and 33 weeks of gestation. It has fewer side effects than drugs previously used for this purpose (such as ritodrine, salbutamol and terbutaline). Oxytocin has not been found to be useful for improving breastfeeding success.