Dinoprost (PGF2α): veterinary dose and monograph

At a glance

Drug class

Veterinary drug

Also known as

Lutalyse, Dinoprost tromethamine, Prostaglandin F2-alpha

Species with doses

Dogs, Cats, Cattle, Horses, Goats, Sheep and Pigs

Routes

IM, SC

Last reviewed

1 October 2026

Indications

• Oestrus synchronisation in cattle (and small ruminants)
• Treatment of open pyometra / chronic endometritis / luteal cysts
• Induction of abortion (feedlot/mismating) or parturition
• Expulsion of mummified fetus / retained placenta (selected cases)
• Canine open-cervix pyometra (with antibiotics, veterinary supervision)

Dinoprost (PGF2α) 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

• Open-cervix pyometra (with antibiotics): Papich 5e: 0.1–0.2 mg/kg SC once daily for 5 days. Plumb’s p.417 (Feldman 2000): day 1 0.1 mg/kg SC, day 2 0.2 mg/kg, days 3–7 0.25 mg/kg once daily, with E. coli-effective antibiotics continued 14 days after; open cervix, bitches ≤6 years, not critically ill; re-evaluate at 7 and 14 days. Natural PGF2α only (cloprostenol doses are far smaller).

Cats

• Open-cervix pyometra: Papich 5e: 0.1–0.25 mg/kg SC once daily for 5 days. Plumb’s p.417 (Nelson & Feldman): 0.1 mg/kg SC initially, then 0.25 mg/kg once daily for 5 days with bactericidal antibiotics; not for cats over 8 years or severely ill; re-evaluate at 2 weeks.

Cattle

• Oestrus synchronisation / luteolysis: Papich 5e and Plumb’s p.417 (Lutalyse label): 25 mg (5 mL) IM once, or twice 10–12 days apart; breed at detected oestrus or about 80 h after the second injection. Requires a functional corpus luteum. Label: no meat or milk withdrawal. Abortifacient; women of child-bearing age and asthmatics must not handle.
• Pyometra / termination of pregnancy: Papich 5e: 25 mg IM once for pyometra or pregnancy termination. Plumb’s p.417: pyometra 25 mg IM (uterus evacuates within 24 h) or twice 8 h apart; abortion 25–30 mg IM at 5–150 days (after 150 days combine with 25 mg dexamethasone); induction of parturition 25–30 mg IM.

Horses

• Luteolysis / oestrus control: Papich 5e and Plumb’s p.417 (label): 1 mg per 45 kg IM (≈10 mg for a 450 kg mare) — oestrus in 2–4 days, ovulation 8–12 days later; 10 mg total for luteolysis (Dascanio 2009); two-injection synchronisation 5 mg on days 1 and 16 (Bristol 1987). Expect transient sweating and colic-like signs.

Goats

• Oestrus synchronisation: Plumb’s p.417 (Carson 1986): does 8 mg IM on day 4 of the cycle and again 11 days later; oestrus about 2 days after the last injection. Pseudopregnancy (hydrometra) 5 mg IM once (Tibary 2009). Goats depend on the CL throughout pregnancy — dinoprost aborts at any stage.
• Termination of pregnancy / induction of kidding: Plumb’s p.417 (Drost 1986): abortion 5–10 mg IM at any stage (abortion in 4–5 days); induction of parturition 2.5–20 mg on days 144–149 (20 mg gives a more predictable interval).

Sheep

• Oestrus synchronisation: Plumb’s p.417 (Carson 1986): ewes 8 mg IM on day 5 of the cycle and again 11 days later; oestrus about 2 days after the last injection.
• Termination of early pregnancy: Plumb’s p.417 (Drost 1986): ewes in the first two months of pregnancy 10–15 mg IM; abortion within 72 h. Later pregnancy is less CL-dependent in sheep.

Pigs

• Induction of farrowing: Papich 5e (label): 10 mg (2 mL) IM once; farrowing within about 30 h. Plumb’s p.417: 10–25 mg IM 2–6 days before expected farrowing (Drost 1986). Abortion: 5–10 mg IM.

Buffalo

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

• Oestrus synchronisation / luteolysis: Papich 5e and Plumb’s p.417 (Lutalyse label): 25 mg (5 mL) IM once, or twice 10–12 days apart; breed at detected oestrus or about 80 h after the second injection. Requires a functional corpus luteum. Label: no meat or milk withdrawal. Abortifacient; women of child-bearing age and asthmatics must not handle.
• Pyometra / termination of pregnancy: Papich 5e: 25 mg IM once for pyometra or pregnancy termination. Plumb’s p.417: pyometra 25 mg IM (uterus evacuates within 24 h) or twice 8 h apart; abortion 25–30 mg IM at 5–150 days (after 150 days combine with 25 mg dexamethasone); induction of parturition 25–30 mg IM.

Contraindications

Pregnant animals where abortion is NOT intended (potent luteolytic/abortifacient). Asthmatic or pregnant HUMAN handlers must avoid skin contact. Acute respiratory disease (bronchoconstriction). Closed-cervix pyometra in the bitch (risk of uterine rupture — only with veterinary judgement and cervix open). Known hypersensitivity.

Species-specific warnings

Horses: Mares commonly show transient sweating, colic and restlessness even at correct doses — forewarn owners; keep the horse calm.

Dogs: Use only for open-cervix pyometra under supervision — risk of uterine rupture if the cervix is closed. Expect panting, vomiting and restlessness for ~30–60 min after each dose.

Adverse effects

• In animals: restlessness, sweating, abdominal discomfort, transient hypersalivation, mild colic (esp. horses), dyspnoea
• Abortion if pregnant
• In bitches: panting, vomiting, defecation/urination, vocalisation for 30–60 min post-injection
• Bronchospasm; injection-site reactions

Drug interactions

• Oxytocin / other uterotonics: additive uterine contraction
• Other prostaglandins: additive luteolytic/smooth-muscle effects
• NSAIDs (prostaglandin-synthesis inhibitors): theoretically blunt endogenous prostaglandin pathways (clinical effect minor)

Pregnancy and lactation

Abortifacient by design — only use in pregnancy when termination/induction is intended. A genuine hazard to pregnant human handlers (transdermal absorption) — strict glove use.

Monitoring

• Reproductive response (oestrus signs, progesterone, uterine drainage/ultrasound)
• Transient side effects after injection (especially horses and bitches)
• Confirmation of intended (non-)pregnancy before use
• Handler safety practices (gloves; asthmatic/pregnant staff avoid contact)

Toxicity and overdose

Overdose intensifies smooth-muscle effects — severe colic/abdominal pain, dyspnoea/bronchospasm, hypersalivation, sweating, tachycardia and, in pregnant animals, abortion. Horses are particularly prone to transient colic-like signs even at therapeutic doses.

Management: No specific antidote. Supportive — keep the animal calm, manage colic/respiratory signs; bronchodilators/oxygen for significant bronchospasm. Effects are usually short-lived (minutes to ~1 h). Human exposure: wash skin, and asthmatic/pregnant individuals should seek medical advice.

Clinical pearls

• The workhorse luteolytic for cattle oestrus synchronisation — classically two doses 11 days apart
• For canine pyometra, reserve for OPEN-cervix cases with antibiotics and warn owners about the dramatic but brief side effects after each dose
• Handler safety is a real issue: absorbed through skin, it can trigger asthma attacks and abortion — gloves are mandatory and pregnant/asthmatic staff must not handle it
• Expect transient sweating/colic in horses — usually self-limiting within an hour
• Cloprostanol (a synthetic analogue, already in the formulary) is an alternative with similar indications at much smaller microgram doses

Mechanism of action

Binds FP prostaglandin receptors on the corpus luteum to cause luteolysis (regression of the CL), abruptly lowering progesterone so the animal returns to oestrus or, if pregnant, loses pregnancy support. It also stimulates myometrial (uterine) and other smooth-muscle contraction — emptying the uterus (pyometra/retained material) and contributing to the bronchospasm and GI effects seen as side effects.

Formulations and products

• Injection 5 mg/mL (dinoprost tromethamine)
• Lutalyse (Zoetis) — Dinoprost tromethamine 5 mg/mL, Injection

Storage

Injection: 15–30 °C, protect from light; do not freeze.

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