|Trade names||Pitocin, Syntocinon, others|
|Intranasal, IV, IM|
|Metabolism||Liver and elsewhere (via oxytocinases)|
|Elimination half-life||1–6 min (IV)|
~2 h (intranasal)
|Excretion||Biliary and kidney|
|Chemical and physical data|
|Molar mass||1007.19 g·mol−1|
|3D model (JSmol)|
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.
Oxytocin injection (synthetic) is contraindicated in any of these conditions:
Oxytocin is relatively safe when used at recommended doses, and side effects are uncommon. These maternal events have been reported:
Excessive dosage or long-term administration (over a period of 24 hours or longer) has been known to result in tetanic uterine contractions, uterine rupture, postpartum hemorrhage, and water intoxication, sometimes fatal.
Oxytocin was added to the Institute for Safe Medication Practices's list of High Alert Medications in Acute Care Settings in 2012. The list includes medications that have a high risk for harm if administered incorrectly.
During pregnancy, increased uterine motility has led to decreased heart rate, cardiac arrhythmia, seizures, brain damage, and death in the fetus or neonate.
Use is linked to an increased risk of postpartum depression in the mother.
Certain learning and memory functions are impaired by centrally administered oxytocin. Also, systemic oxytocin administration can impair memory retrieval in certain aversive memory tasks. However, oxytocin does seem to facilitate learning and memory specifically for social information. Healthy males administered intranasal oxytocin show improved memory for human faces, in particular happy faces.
One IU of oxytocin is the equivalent of about 2 μg or mcg of pure peptide.
Oxytocin's uterine-contracting properties were discovered by British pharmacologist Henry Hallett Dale in 1906. Oxytocin's milk ejection property was described by Ott and Scott in 1910 and by Schafer and Mackenzie in 1911.
Oxytocin was the first polypeptide hormone to be sequenced or synthesized. Du Vigneaud was awarded the Nobel Prize in 1955 for his work.
The word "oxytocin" was coined from the term oxytocic. Greek ὀξύς, oxys, and τόκος, tokos, meaning "quick birth".
In African countries, some oxytocin products were found to be counterfeit medications.
The trust-inducing property of oxytocin might help those with social anxiety and depression, anxiety, fear, and social dysfunctions, such as generalized anxiety disorder, post-traumatic stress disorder, and social anxiety disorder, as well as autism and schizophrenia, among others. However, in one meta-analysis only autism spectrum disorder showed a significant combined effect size.
People using oxytocin show improved recognition for positive social cues over threatening social cues and improved recognition of fear.
Oxytocin can be delivered to humans via nasal spray following which it crosses the blood–brain barrier. ... In a double-blind experiment, oxytocin spray increased trusting behavior compared to a placebo spray in a monetary game with real money at stake.
Recent studies also highlight remarkable anxiolytic and prosocial effects of intranasally administered OT in humans, including increased 'trust', decreased amygdala activation towards fear-inducing stimuli, improved recognition of social cues and increased gaze directed towards the eye regions of others (Kirsch et al., 2005; Kosfeld et al., 2005; Domes et al., 2006; Guastella et al., 2008).