Oxytocin

alpha-hypophamine

Hormonal AgentIMIVSCIntranasalDogsCatsSmall MammalsBirdsReptilesHorsesCattleSwineSheepGoats

Also known as: Pitocin · Syntocinon · alpha-hypophamine · oxytocinum

Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference

0.5-3 Units SC or IM every 30-60 minutes, best based upon the results of tokodynamometry.SC/IM· q30-60m· Until parturition is complete

0.5–3 unit — Fixed dose per animal (not weight-scaled)

Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.

Dosing by species

🌎 NA — North America🌍 EU — Europe

Dogs

Indication	Dose	Route	Frequency	Duration	Region
To augment uterine contractions during parturition	0.5-3 Units SC or IM every 30-60 minutes, best based upon the results of tokodynamometry.	SC/IM	q30-60m	Until parturition is complete	🌎 NA
For uterine inertia (if no fetuses in birth canal, cervix dilated, obstruction ruled out)	5-20 Units (depending on size of animal) IM or as an IV drip (10 Units/liter) beginning as a slow drip and gradually increasing until effective contractions are observed. If no response to IM injection in 30 minutes, may repeat along with 10% dextrose IV slowly. If no response again in 30 minutes, repeat IM again.	IM/IV	As directed	—	🌎 NA
For uterine inertia (mini-dose protocol)	0.25 Units (total dose) SC or IM to a maximum dose of 4 Units per bitch. Generally not given more frequently than hourly.	SC/IM	q1h	—	🌎 NA
To induce milk let-down (adequate milk production, tolerates nursing)	Oxytocin nasal spray: 5-10 minutes prior to nursing three times daily	Intranasal	TID	—	🌎 NA
For secondary agalactia	0.25-1 Unit (total dose) SC q2h.	SC	q2h	—	🌎 NA
For adjunctive treatment of acute metritis	0.5-5 Units (total dose) IM	IM	Once	—	🌎 NA
To promote uterine involution after uterine prolapse manual reduction	0.5-5 Units IM (Traas & O'Conner 2009) OR 5-10 Units (total dose) IM (Shaw 2007)	IM	Once	—	🌎 NA

For uterine inertia (if no fetuses in birth canal, cervix dilated, obstruction ruled out): Some texts recommend giving calcium gluconate (2-10 mL slowly IV) prior. If no response, perform C-section.
For uterine inertia (mini-dose protocol): Given 15 minutes after calcium gluconate 10% (1 mL/5.5 kg SC). Higher doses can cause tetanic contractions.
For secondary agalactia: Remove neonates for 30 mins post-injection. Often used with metoclopramide 0.1-0.2 mg/kg SC q12h.
For adjunctive treatment of acute metritis: May be used if birth occurred less than 24 hours prior.
To promote uterine involution after uterine prolapse manual reduction: Given following successful manual reduction.

Cats

Indication	Dose	Route	Frequency	Duration	Region
To promote uterine involution after uterine prolapse manual reduction	0.5-5 Units IM OR 5-10 Units (total dose) IM	IM	Once	—	🌎 NA
To treat primary uterine inertia	0.25 Units (total dose) SC or IM to a maximum dose of 4 Units per queen. Generally not given more frequently than hourly.	SC/IM	q1h	—	🌎 NA
For adjunctive treatment of metritis	0.5-5 Units IM	IM	Once	—	🌎 NA
To induce milk let-down (secondary agalactia)	0.25-1 Unit (total dose) SC q2h.	SC	q2h	—	🌎 NA

To promote uterine involution after uterine prolapse manual reduction: Extrapolated from dog doses.
To treat primary uterine inertia: Given 15 minutes after calcium gluconate.
For adjunctive treatment of metritis: May be used if birth occurred less than 24 hours prior.
To induce milk let-down (secondary agalactia): Remove neonates for 30 mins post-injection. Often used with metoclopramide.

Small Mammals

Indication	Dose	Route	Frequency	Duration	Region
Uterotonic / Obstetrical use (Mice, Rats, Gerbils, Hamsters, Guinea pigs, Chinchillas)	0.2-3 Units/kg IV, IM or SC	IV/IM/SC	Once	—	🌎 NA

Birds

Indication	Dose	Route	Frequency	Duration	Region
As a uterotonic agent	0.5 Units/kg IM; may repeat in 60 minutes	IM	May repeat in 60m	—	🌎 NA
For egg expulsion	0.01-0.1 mL once IM.	IM	Once	—	🌎 NA

For egg expulsion: Should be administered with Vitamin A and calcium (injectable).

Reptiles

Indication	Dose	Route	Frequency	Duration	Region
For egg binding	1-10 Units/kg IM.	IM	As needed	—	🌎 NA
To induce oviposition	1-30 Units/kg (10 Units/kg appears effective in many chelonians). May have to repeat in several hours.	IM	May repeat in several hours	—	🌎 NA

For egg binding: Given in combination with calcium glubionate. Use care with multiple injections. Not as effective in lizards.
To induce oviposition: Risk of oviduct rupture if cloaca is obstructed.

Horses

Indication	Dose	Route	Frequency	Duration	Region
To augment or initiate uterine contractions during parturition in properly evaluated mares	2.5-5 Units IV, every 15-20 minutes until foal is born	IV	q15-20m	Until foal is born	🌎 NA
To prevent luteolysis (prolong corpus luteum lifespan)	60 Units (3 ml) IM once daily from day 7 to day 14 post-ovulation.	IM	q24h	Days 7 to 14 post-ovulation	🌎 NA
For evacuation of uterine fluid	20 Units IV or IM one to three times a day	IV/IM	SID to TID	—	🌎 NA
To aid in removal of retained fetal membranes	30-100 Units in 1 liter of normal saline IV over 30-60 minutes OR 10-120 Units IM OR 10-40 Units by IV bolus	IV/IM	Once	—	🌎 NA
To aid in removal of retained fetal membranes (alternative)	20 Units IV or IM given every hour beginning 2-3 hours after foaling. Repeat as needed.	IV/IM	q1h	As needed	🌎 NA
For mild to moderate cases of acute post-partum metritis	20 Units IM 3-4 times a day for 2-3 days	IM	TID to QID	2-3 days	🌎 NA
To treat esophageal obstruction ('choke')	0.11-0.22 Units/kg IV once	IV	Once	—	🌎 NA

To prevent luteolysis (prolong corpus luteum lifespan): Ovulation must be documented closely.
To aid in removal of retained fetal membranes: Large dose IV boluses are not recommended as they may cause uterine spasm and abdominal discomfort.
To treat esophageal obstruction ('choke'): Given with N-butylscopolammonium bromide. Avoid or reduce dose in mares. Do not use in pregnant mares.

Cattle

Indication	Dose	Route	Frequency	Duration	Region
For retained placenta	40-60 Units oxytocin q2h as necessary.	IM/IV	q2h	As necessary	🌎 NA
To reduce incidence of retained placenta	20 Units IM immediately following calving and repeated 2-4 hours later	IM	Once, then repeat in 2-4h	—	🌎 NA
For mild to moderate cases of acute post-partum metritis	20 Units IM 3-4 times a day for 2-3 days	IM	TID to QID	2-3 days	🌎 NA
To augment uterine contractions during parturition	30 Units IM; repeat no sooner than 30 minutes if necessary	IM	q30m	As necessary	🌎 NA
For obstetrical use in cows	100 Units IV, IM or SC	IV/IM/SC	Once	—	🌎 NA
For milk let-down in cows	10-20 Units IV	IV	Once	—	🌎 NA

For retained placenta: Often used with IV calcium. Limited value after 48 hours postpartum.

Swine

Indication	Dose	Route	Frequency	Duration	Region
For adjunctive treatment of agalactia syndrome (MMA) in sows	30-40 Units per sow at 3-4 hours	IM/IV	q3-4h	—	🌎 NA
For adjunctive treatment of agalactia syndrome (MMA) in sows (alternative)	20-50 Units IM or 5-10 Units IV	IM/IV	Once	—	🌎 NA
For retained placenta in patients with uterine atony	20-30 Units oxytocin q2-3h as necessary	IM/IV	q2-3h	As necessary	🌎 NA
To augment uterine contractions during parturition	10 Units IM; repeat no sooner than 30 minutes if necessary	IM	q30m	As necessary	🌎 NA
For obstetrical use in sows	30-50 Units IV, IM or SC	IV/IM/SC	Once	—	🌎 NA
For mild to moderate cases of acute post-partum metritis	5-10 Units IM 3-4 times a day for 2-3 days	IM	TID to QID	2-3 days	🌎 NA
For mild to moderate cases of acute post-partum metritis (alternative)	5 Units IM; may need to be repeated as effect may be as short as 30 minutes	IM	As needed	—	🌎 NA
For milk let-down in sows	5-20 Units IV	IV	Once	—	🌎 NA

For retained placenta in patients with uterine atony: Use with broad-spectrum antibiotics.

Sheep

Indication	Dose	Route	Frequency	Duration	Region
For retained placenta in patients with uterine atony	10-20 Units oxytocin.	IM/IV	Once	—	🌎 NA
For mild to moderate cases of acute post-partum metritis	5-10 Units IM 3-4 times a day for 2-3 days	IM	TID to QID	2-3 days	🌎 NA

For retained placenta in patients with uterine atony: Limited value after 48 hours postpartum. Note for CAMELIDS (NW): 5-10 Units IM at 10-minute intervals for retained placenta (Adams 2008).

Goats

Indication	Dose	Route	Frequency	Duration	Region
For retained placenta in patients with uterine atony	10-20 Units oxytocin.	IM/IV	Once	—	🌎 NA
For mild to moderate cases of acute post-partum metritis	5-10 Units IM 3-4 times a day for 2-3 days	IM	TID to QID	2-3 days	🌎 NA
To control post-extraction cervical and uterine bleeding after internal manipulations	10-20 Units IV, may repeat SC in 2 hours	IV/SC	Once, may repeat in 2h	—	🌎 NA

For retained placenta in patients with uterine atony: Limited value after 48 hours postpartum.

Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.

Recording this consult? VetSheet's AI writes the drug, dose and duration straight into a structured visit note.See how VetSheet works

Overview

Oxytocin is a nonapeptide hypothalamic hormone synthesized in the paraventricular and supraoptic nuclei and stored in the posterior pituitary gland. In veterinary medicine, it is primarily utilized as a uterotonic agent to induce or enhance uterine contractions during parturition, treat postpartum retained placenta and metritis, promote uterine involution, and facilitate milk let-down in cases of agalactia.

Clinical Pearls:

Mini-dosing is preferred: Modern veterinary obstetrics strongly advocates for "mini-doses" (e.g., 0.25-4 Units total in dogs) rather than historical high doses. High doses can cause tetanic, ineffective uterine contractions that compromise fetal oxygen supply via placental compression and increase the risk of uterine rupture.
Calcium dependency: Oxytocin's efficacy is highly dependent on extracellular calcium. Hypocalcemia or hypoglycemia must be corrected prior to administration. Calcium increases the strength of contractions, while oxytocin increases the frequency.
Cervical status: Oxytocin should never be administered if the cervix is closed or if there is an uncorrected obstructive dystocia.

Mechanism of action

Oxytocin exerts its effects by binding to specific G-protein coupled oxytocin receptors (OXTR) on the cell membrane of uterine myofibrils and myoepithelial cells of the mammary gland.

Uterine Contraction: Binding to OXTR activates the Gq/11 pathway → stimulates Phospholipase C (PLC) → increases inositol triphosphate (IP3) and diacylglycerol (DAG) → triggers the release of intracellular calcium from the sarcoplasmic reticulum. Calcium binds to calmodulin, activating Myosin Light Chain Kinase (MLCK), leading to smooth muscle contraction. The threshold for oxytocin-induced contraction is significantly lowered late in pregnancy due to upregulation of oxytocin receptors by high estrogen levels.
Milk Let-down: Oxytocin stimulates the contraction of myoepithelial cells surrounding the mammary alveoli, forcing milk into the larger ducts and cisterns. It does not have galactopoietic (milk-producing) properties.

Safety & warnings

Contraindications

Dystocia due to abnormal fetal presentation (unless corrected)
Closed or unrelaxed cervix
Known hypersensitivity to oxytocin
Significant cephalopelvic disproportion
Obstetrical emergencies where surgical intervention (C-section) is warranted
Pregnancy (for nasally administered oxytocin)

Adverse effects

Uterine cramping and discomfort
Tetanic uterine contractions (at high doses)
Uterine rupture
Fetal compromise or death (due to placental compression)
Water intoxication (with prolonged high-dose infusions)
Hypersensitivity reactions (more common with non-synthetic products)

Precautions

Critical Warning: Always evaluate the patient for obstructive dystocia and ensure the cervix is dilated before administration.

Metabolic Status: Treat hypoglycemia or hypocalcemia before using oxytocin, as uterine fatigue is often secondary to these metabolic deficits.
Water Intoxication: While oxytocin has minimal antidiuretic properties, water intoxication can occur if administered at too rapid a rate or if excessively large volumes of electrolyte-free IV fluids are given concurrently. Signs include depression, coma, and seizures.
Fetal Monitoring: Monitor fetal heart rates if possible, as excessive uterine contractions can cause fetal hypoxia.

Drug interactions

Thiopental

May delay thiopental anesthesia (reported in humans; clinical significance in animals is not firmly established).

Vasoconstrictors (Sympathomimetics)

Concurrent use post-partum may result in severe hypertension. Monitor closely.

Monitoring

Uterine contractions (frequency, duration, and strength via tokodynamometry if available)
Status of the cervix (must be dilated)
Fetal monitoring (heart rate/distress)
Maternal calcium and glucose levels

Pharmacokinetics

Absorption

Destroyed in the GI tract; must be administered parenterally. Intranasal absorption can be erratic. Uterine response is almost immediate after IV administration, and within 3-5 minutes following IM administration.

Distribution

Distributed throughout the extracellular fluid. Small quantities cross the placenta and enter the fetal circulation.

Metabolism

Metabolized rapidly in the liver and kidneys. A circulating enzyme, oxytocinase, can also destroy the hormone.

Elimination

Very small amounts are excreted unchanged in the urine. Duration of effect in dogs is ~13 minutes (IV) and ~20 minutes (IM/SC).

Overdose

Effects of overdosage on the uterus depend on the stage of the uterus and the position of the fetus(es).

Uterine Effects: Hypertonic or tetanic contractions can occur, leading to tumultuous labor, uterine rupture, fetal injury, or fetal death due to compromised placental blood flow.
Water Intoxication: Can occur if large doses are infused for a long period, especially with large volumes of electrolyte-free IV fluids.
- Early signs: Listlessness, depression.
- Severe signs: Coma, seizures, death.
- Treatment: Stop oxytocin therapy, restrict water access. Severe cases may require osmotic diuretics (mannitol, urea, dextrose) with or without furosemide.

Available products

Formulations

Injection (solution)
Nasal spray

Veterinary

Oxytocin for Injection: 20 USP Units/mL in 10 mL, 30 mL, and 100 mL vials

Human-labeled

Oxytocin Solution for Injection: 10 Units/mL in 1 mL amps, 3 mL & 10 mL vials and 10 mL multiple-dose vials (Pitocin®)

Regulatory status

No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

Storage & stability

Store at temperatures less than 25°C (77°F); do not freeze. Some manufacturers recommend refrigeration (2-8°C), but some products are stable for up to 5 years if stored at less than 26°C.

Client information

Oxytocin is a potent hormone used to help your pet during labor or to help with milk let-down.

Professional Monitoring Required: It should only be used under the direct guidance or administration of a veterinarian who can adequately monitor its effects.
Risks of Misuse: Giving oxytocin when a fetus is stuck or the birth canal is not fully open can cause severe complications, including rupture of the uterus and death of the unborn babies.
Nasal Spray: If you are prescribed the nasal spray for milk let-down, administer it exactly as directed, usually 5-10 minutes before nursing.

VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.