Oxytocin: veterinary dose and monograph

At a glance

Drug class

Veterinary drug

Also known as

Pitocin, Syntocinon

Species with doses

Dogs, Cats, Cattle, Horses, Goats, Sheep, Pigs, Birds, Rabbits, Guinea pigs, Reptiles, Chinchillas, Hamsters, Rats, Mice and Gerbils

Routes

SC, IM, IV

Last reviewed

1 October 2026

Indications

• Augmentation of uterine contractions (uterine inertia)
• Retained placenta / fetal membranes
• Acute post-partum metritis (adjunct)
• Promote uterine involution after prolapse reduction
• Milk let-down (agalactia)
• Esophageal "choke" in horses (with N-butylscopolammonium)

Oxytocin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Uterine inertia (mini-dose): Plumb’s p.928 (Davidson 2009): mini-doses starting at 0.25 U total SC or IM up to a maximum of 4 U per bitch, no more often than hourly, guided by uterine/fetal monitoring; give calcium gluconate (1 mL/5.5 kg SC) first to strengthen contractions. Larger doses or IV boluses cause tetanic contractions. Papich 5e lists 5–20 U per dog IM/SC q30min (label 5–30 U). Rule out obstruction before any oxytocin.
• Augment labour contractions: Plumb’s p.928 (Davidson 2004): 0.5–3 U SC or IM every 30–60 min, ideally guided by tocodynamometry. Only when the birth canal is clear and the cervix dilated.
• Acute metritis (within 24 h post-partum): Plumb’s p.928 (Traas & O’Conner 2009): 0.5–5 U total IM if whelping was less than 24 h ago, with broad-spectrum antibiotics and fluids; after uterine prolapse reduction 0.5–5 U (or 5–10 U, Shaw) IM to promote involution.
• Milk let-down (secondary agalactia): Plumb’s p.928 (Davidson 2009): secondary agalactia 0.25–1 U total SC q2h; remove the pups for 30 min after each injection, then encourage suckling; metoclopramide 0.1–0.2 mg/kg SC q12h promotes milk production. Papich 5e: 2–5 U per dog IM 15–30 min before nursing.

Cats

• Uterine inertia (mini-dose): Plumb’s p.928 (Davidson 2009, dogs and cats): 0.25 U up to a maximum of 4 U per queen SC or IM, no more often than hourly, after calcium gluconate. Papich 5e: 2.5–3 U per cat IM or IV, repeat up to three times every 30–60 min (max 3 U per dose).

Cattle

• Retained placenta: 40–60 IU per cow. Of limited value after 48 h post-partum (uterine sensitivity drops). WITHDRAWAL — Plumb's p.930: "There are no milk or meat withdrawal times specified for oxytocin." Oxytocin is an endogenous peptide and is cleared rapidly; the FDA-approved products carry no withdrawal requirement.
• Augment parturition: Plumb’s p.928 (Wheaton 1989) and Papich 5e: 30 U IM, repeated no sooner than 30 min if needed (label lists 100 U per cow). Rule out malpresentation and ensure the cervix is dilated. No meat or milk withdrawal specified (Plumb’s).
• Milk let-down: Plumb’s p.928 (label) and Papich 5e: 10–20 U per cow IV (or IM, Papich). No withdrawal specified.

Horses

• Induction of parturition (properly evaluated mares): Plumb’s p.929 (McCue 2003): induction 2.5–5 U IV every 15–20 min until the foal is born — only in mares confirmed ready to foal. Papich 5e: uterine contractions 20 U IM (label 100 U).
• Retained fetal membranes: Plumb’s p.929: 20 U IV or IM every hour starting 2–3 h after foaling (McCue); 30–100 U in 1 L saline IV over 30–60 min, 10–120 U IM or 10–40 U IV bolus — avoid large IV boluses (uterine spasm, colic) (Perkins). Papich 5e: 30–40 U IM at 60–90-min intervals, or 80–100 U in 500 mL saline IV.
• Esophageal obstruction (choke): UNITS/kg. Plumb’s p.929 (Beard 2008): oxytocin 0.11–0.22 U/kg IV once with hyoscine butylbromide 0.3 mg/kg IV; avoid or greatly reduce the dose in mares and never use in pregnant mares.

Goats

• Acute post-partum metritis / uterine involution: Plumb’s p.929 (Hameida et al. 1986): sheep & goats 5–10 U IM 3–4 times a day for 2–3 days. Retained placenta: 10–20 U (McClary 1986). Goats, post-fetotomy uterine bleeding: 10–20 U IV, may repeat SC in 2 h (Franklin 1986). Papich 5e: 5–10 U IM. (The 20 U figure previously shown is the CATTLE dose.)

Sheep

• Acute post-partum metritis / uterine involution: Plumb’s p.929 (Hameida et al. 1986): sheep & goats 5–10 U IM 3–4 times a day for 2–3 days. Retained placenta with uterine atony: 10–20 U (McClary 1986), of limited value after 48 h. Papich 5e: small ruminants 5–10 U IM. (The 20 U figure previously shown is the CATTLE dose.)

Pigs

• MMA / agalactia in sows: Plumb’s p.929: MMA 20–50 U IM or 5–10 U IV (Einarsson); 30–40 U per sow every 3–4 h (Powe); milk let-down 5–20 U IV (label). Papich 5e: sows 5–10 U IM (label 30–50 U). No withdrawal specified.
• Retained placenta: Plumb’s p.929 (McClary 1986): 20–30 U q2–3h as necessary with broad-spectrum antibiotics, when there is uterine atony. Augmenting farrowing: 10 U IM, not repeated sooner than 30 min (Wheaton).

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Retained placenta: 40–60 IU per cow. Of limited value after 48 h post-partum (uterine sensitivity drops). WITHDRAWAL — Plumb's p.930: "There are no milk or meat withdrawal times specified for oxytocin." Oxytocin is an endogenous peptide and is cleared rapidly; the FDA-approved products carry no withdrawal requirement.
• Augment parturition: Plumb’s p.928 (Wheaton 1989) and Papich 5e: 30 U IM, repeated no sooner than 30 min if needed (label lists 100 U per cow). Rule out malpresentation and ensure the cervix is dilated. No meat or milk withdrawal specified (Plumb’s).
• Milk let-down: Plumb’s p.928 (label) and Papich 5e: 10–20 U per cow IV (or IM, Papich). No withdrawal specified.

Birds

• Egg retention / dystocia: Plumb’s p.930 (Pollock 2007): 0.5 U/kg IM as a uterotonic, may repeat in 60 minutes. Correct hypocalcaemia first (calcium IM), warm the bird and give humidity; confirm the egg can pass.

Rabbits

• Dystocia — Plumb’s (total dose per rabbit): Plumb’s 10e p.979 (extra-label): calcium glubionate 10%, 5–10 mL PO 30 minutes before giving oxytocin 1–3 units IM — TOTAL dose per rabbit, NOT units/kg. Confirm the birth canal is clear first.
• Uterine inertia (doe) — Carpenter’s (per kg): Carpenter’s Exotic Animal Formulary (rabbit table): 0.1–3 U/kg SC or IM — PER KG, not per doe — for delayed but unobstructed parturition. REFERENCE CONFLICT: Plumb’s 10e p.979 gives 1–3 units TOTAL per rabbit (row above); for a 4 kg doe Carpenter’s upper figure is 12 units. Confirm the birth canal is clear first; calcium may be given beforehand.

Guinea pigs

• Uterine inertia / dystocia: Plumb's p.929 (Adamcak & Otten 2000): Mice/Rats/Gerbils/Hamsters/Guinea pigs/Chinchillas 0.2–3 IU/kg IV, IM or SC. Ensure pelvic canal is patent before use.

Reptiles

• Egg retention / dystocia: Plumb's extra-label: 1–10 IU/kg IM in chelonians / lizards / snakes. Pre-treat with calcium gluconate IM 30 min before. Surgical removal if no response after 2 doses.

Chinchillas

• Uterine inertia / dystocia: Plumb's p.929: 0.2–3 IU/kg IV, IM or SC.

Hamsters

• Uterine inertia / dystocia: Plumb's p.929: 0.2–3 IU/kg IV, IM or SC.

Rats

• Uterine inertia / dystocia: Plumb's p.929: 0.2–3 IU/kg IV, IM or SC.

Mice

• Uterine inertia / dystocia: Plumb's p.929: 0.2–3 IU/kg IV, IM or SC.

Gerbils

• Uterine inertia / dystocia: Plumb's p.929: 0.2–3 IU/kg IV, IM or SC.

Contraindications

Dystocia from abnormal fetal presentation (correct first). Cervix not yet dilated. Hypoglycaemia or hypocalcaemia (treat first). Hypersensitivity. In humans: cephalopelvic disproportion, severe toxaemia.

Species-specific warnings

Dogs: Dose by IU per animal — never weight-based. Confirm cervical patency before use in dystocia. Risk of uterine rupture if obstructed delivery.

Cats: Cats more prone to uterine rupture — use 0.25–2 IU IM/SC per animal. Avoid repeated large doses.

Cattle: Retained placenta: 20–40 IU IM. Hypocalcaemia (milk fever) blunts response — correct calcium first. PGF2α often a better choice >12 h post-calving.

Horses: Most effective for retained placenta <12 h post-foaling. CRI (60–100 IU in 1 L saline) is gentler than bolus.

Pigs: Farrowing distress / agalactia: 5–10 IU IM. Standard ecbolic for retained piglets.

Goats: Same dose range as sheep. Dystocia: 5–10 IU IM after cervical patency confirmed.

Adverse effects

• Uterine cramping (high doses or repeat boluses)
• Uterine rupture (excessive dose)
• Placental compromise → fetal hypoxia (high IV bolus)
• Hypersensitivity (non-synthetic products)
• Maternal hypotension (rapid IV)

Drug interactions

• Prostaglandin F2-alpha (cloprostenol, dinoprost): synergistic — used together for retained placenta, pyometra
• Calcium gluconate (IV): improves uterine response to oxytocin in hypocalcaemic dams
• Inhalant anaesthetics (halothane, isoflurane): reduce uterine response to oxytocin
• Tocolytics (clenbuterol, ritodrine): antagonise oxytocin effect
• Other ecbolic agents (ergonovine, methylergonovine): additive uterine contraction — used in equine third-stage haemorrhage

Pregnancy and lactation

Use at TERM only — premature dosing risks uterine rupture, fetal hypoxia from prolonged tetanic contraction, abruption. Required cervical patency before use — closed cervix = uterine rupture risk. Safe peri-partum and post-partum at indicated doses. Use lower end of dose range in cats (rupture reports).

Monitoring

• Cervical patency confirmed before every dose in dystocia
• Fetal heart rate (if monitor available) during induction
• Maternal HR, BP, respiratory effort
• Uterine tone — palpate / monitor — discontinue if tetanic
• Calcium status — hypocalcaemia blunts response (give IV Ca gluconate first if low)
• Post-partum: monitor for retained placenta, haemorrhage, mastitis

Toxicity and overdose

Overdose: uterine tetany (sustained contraction), uterine rupture (especially with obstructed delivery / fetal malposition), fetal distress, water intoxication (antidiuretic effect at high IV doses — hyponatraemia, seizures), maternal hypotension (rapid IV bolus), arrhythmias. Anaphylaxis rare. Cats and dogs: uterine rupture if used with obstructed delivery — always confirm cervical patency and absence of obstruction before dosing.

Management: Discontinue. Manage uterine tetany: tocolytic (clenbuterol, ritodrine, or epidural lidocaine), terbutaline 0.01 mg/kg SC. Surgical intervention for rupture / retained fetus. Water intoxication: stop IV fluids, hypertonic saline if severe hyponatraemia, anti-seizure therapy. Supportive care.

Clinical pearls

• OXYTOCIN IS DOSED IN IU PER ANIMAL — not mg/kg. Bitch / queen: 0.25–4 IU IM/SC per animal for uterine inertia or milk let-down
• Mare retained placenta: 20 IU IV/IM q15–30 min, OR 60–100 IU in 1 L saline IV drip — most effective <12 h after foaling
• Cow retained placenta: 20–40 IU IM/IV — less effective >12 h after calving; PGF2α (cloprostenol) often more useful
• CONFIRM CERVICAL PATENCY before use in dystocia — closed cervix + oxytocin = uterine rupture
• Hypocalcaemia (eclampsia, milk fever): GIVE CALCIUM FIRST — calcium-deficient myometrium will not respond
• Milk let-down (mastitis, agalactia): 0.5–5 IU IM/SC 5 min before suckling/milking
• Half-life is short (~5 min IV) — repeat dosing needed for sustained effect; CRI for prolonged use
• Bitch uterine inertia (primary): 1–2 IU SC then re-evaluate at 15 min — large doses (>20 IU) often counter-productive

Mechanism of action

Synthetic nonapeptide identical to endogenous posterior pituitary oxytocin. Binds oxytocin receptors on myometrium (uterine smooth muscle) and myoepithelial cells of the mammary alveoli. Causes uterine contraction (term, oestrogen-primed uterus is most responsive) and milk let-down (ejection from alveoli into ducts). Mild antidiuretic effect at high doses. Receptor density rises sharply at term — pre-term uterus is poorly responsive.

Formulations and products

• Oxytocin Injection 20 IU/mL

Storage

Refrigerated (2–8 °C) is ideal; room temperature (≤25 °C) acceptable for short periods. Protect from light. Multidose vial: discard 28 days after broaching. Do NOT freeze. Inspect for discoloration before use.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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Frequently asked questions