Oxytocin
Oxytocin receptor agonist (posterior pituitary hormone)
Status
Approved
FDA-approved as Pitocin (1980) for medically indicated induction or strengthening of labour and control of bleeding after birth, and authorised nationally in European countries such as France; it is not approved for elective induction or for any behavioural use.
Evidence
Strong
Decades of clinical use and a Cochrane network meta-analysis of 140 randomized trials underpin its obstetric role, while the largest behavioural trial was negative.
Oxytocin is a nine-amino-acid hormone released from the pituitary that makes the womb contract and milk flow. Synthetic oxytocin (Pitocin) is a standard hospital drug to start or strengthen labour and to control bleeding after birth.
Structure
9 residuesPoint at a bead, or focus the chain and use the arrow keys, to name it. Pick a chemistry to highlight it.
Sequence as text
H-C-Y-I-Q-N-C-P-L-G-NH2
What it is used for
- Induction or strengthening of labour when there is a medical reason (approved)
- Producing uterine contractions and controlling bleeding after delivery (approved)
- Adjunct treatment of incomplete or inevitable miscarriage (approved)
- Social difficulties in autism, given as a nasal spray (studied)
- Boosting trust, bonding or social behaviour in general use (claimed, unproven)
How it works
Oxytocin binds oxytocin receptors on the smooth muscle of the uterus, raising calcium inside the muscle cells and triggering contractions. Receptor numbers rise greatly during pregnancy and peak in early labour, so the response varies widely between women and the infusion must be adjusted carefully. Oxytocin differs from the water-retaining hormone vasopressin at only two of eight amino acids, so large doses can cause water retention and blood pressure effects.
How strong the evidence is
Strong
Pitocin's approval rests on long clinical use for labour induction and bleeding after birth. A Cochrane network meta-analysis of 140 randomized trials in 88,947 women compared drugs for preventing postpartum haemorrhage: about 10.5% of women given oxytocin, the WHO-recommended standard, lost 500 mL of blood or more, versus 7.2% to 7.7% with ergometrine plus oxytocin, carbetocin, or misoprostol plus oxytocin (Gallos 2018). For behaviour, the largest trial (SOARS-B, 290 children and adolescents with autism) found daily intranasal oxytocin for 24 weeks no better than placebo on social or cognitive measures (Sikich 2021, NEJM).
Risks and side effects
- Excessive or prolonged contractions that can distress the baby or rupture the uterus
- Water intoxication with seizures when large doses are infused over long periods
- Heart rhythm disturbances, blood pressure changes, nausea and vomiting
- Slow fetal heart rate and other effects in the newborn
- For labour, must be given by intravenous infusion in hospital with continuous monitoring
Label dosing
Label (labour induction): intravenous infusion starting at 0.5 to 1 milliunit per minute, increased by 1 to 2 milliunits per minute every 30 to 60 minutes until the desired contraction pattern is established.
Regulatory status
| Region | Year | Approved for |
|---|---|---|
| USFDA | 1980 | Medically indicated induction or improvement of labour, and control of postpartum bleeding |
Status by country
| Jurisdiction | Status | Source |
|---|---|---|
| USUnited States | Authorised medicine | Source 2 |
| EUEuropean Union | Authorised in some member states | Source 8 |
| UKUnited Kingdom | Authorised medicine | Source 9 |
| AUAustralia | Authorised medicine | Source 10 |
| CACanada | Authorised medicine | Source 11 |
Trials of Oxytocin to watch
Intranasal oxytocin for chronic pain(opens the source in a new tab)
Evaluating the Efficacy of Intranasal Oxytocin on Chronic Pain
OxyTUTION(opens the source in a new tab)
Oxytocin Substitution Therapy in Patients With Central Diabetes Insipidus
Sublingual oxytocin for PPH(opens the source in a new tab)
Sublingual Oxytocin for the Prevention of Post-partum Hemorrhage
OPIC(opens the source in a new tab)
Oxytocin vs Prostaglandins for Labor Induction of Women With an Unfavorable Cervix After 24h of Cervical Ripening
CBCT-OT RCT(opens the source in a new tab)
Examining Intranasal Oxytocin Augmentation of Brief Couples Therapy for Veterans With PTSD
COPE+OT(opens the source in a new tab)
Oxytocin to Enhance Integrated Treatment for AUD and PTSD
Timeline
2028
2027
2026
1980
- Approved, US (FDA)Medically indicated induction or improvement of labour, and control of postpartum bleeding
Sources
- 01PITOCIN (oxytocin injection, USP) label(opens the source in a new tab)
- 02PITOCIN NDA 018261: approval history(opens the source in a new tab)
- 03Oxytocin-neurophysin 1 proprotein (P01178)(opens the source in a new tab)
- 04Oxytocin (CID 439302)(opens the source in a new tab)
- 05Uterotonic agents for preventing postpartum haemorrhage: a network meta-analysis(opens the source in a new tab)
- 06Intranasal oxytocin in children and adolescents with autism spectrum disorder(opens the source in a new tab)
- 07OXYTOCINE PANPHARMA 5 UI/1 ml, solution injectable(opens the source in a new tab)
- 08Oxytocin (systemic use): List of nationally authorised medicinal products, PSUSA/00010913/202306(opens the source in a new tab)
- 09Oxytocin 10 IU/ml Concentrate for Solution for Infusion: Summary of Product Characteristics(opens the source in a new tab)
- 10SYNTOCINON oxytocin 10 IU/1 mL injection ampoule (13383)(opens the source in a new tab)
- 11Drug Product Database: Oxytocin Injection USP (DIN 00497398)(opens the source in a new tab)
Educational information, not medical advice. Talk to a licensed clinician before starting, stopping or changing any medicine.