Dinoprost Tromethamine
Prostaglandin F2alpha tromethamine
Also known as: Lutalyse Β· In-Synch Β· Amtech Prostamate Β· idinoprostum trometamoli Β· PGF(2alpha) THAM Β· prostaglandin F(2alpha) trometamol Β· U-14583E
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
π NA β North Americaπ EU β Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of pyometra (open cervix, non-critically ill, β€6 years old) | Day 1: 0.1 mg/kg SC once; Day 2: 0.2 mg/kg SC once; Days 3-7: 0.25 mg/kg SC once daily | SC | once daily (escalating dose) | 7 days | π NA |
| Abortifacient (After day 25 or 30) | maximum dosage of 80-100 micrograms/kg SC twice a day | SC | q12h | 6 days or longer | π NA |
| Adjunctive therapy for termination of mid-term pregnancy | 0.1 mg/kg SC three times daily for 3 days and then 0.2 mg/kg SC three times daily to effect | SC | q8h | to effect | π NA |
- Treatment of pyometra (open cervix, non-critically ill, β€6 years old): Use concurrent antibiotics for 14 days after completion. Reevaluate at 7 and 14 days.
- Abortifacient (After day 25 or 30): Start with half the dose for the first day. Monitor side effects carefully.
- Adjunctive therapy for termination of mid-term pregnancy: Given concurrently with 1-3 micrograms/kg misoprostol intravaginally once daily.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of pyometra | Initially 0.1 mg/kg SC, then 0.25 mg/kg SC once a day for 5 days | SC | once daily | 6 days total | π NA |
| Abortifacient | 2 mg (total dose) per cat IM once a day beginning at day 33 | IM | once daily | Not specified | π NA |
- Treatment of pyometra: Give bactericidal antibiotics concurrently. Not recommended in animals >8 yrs old.
- Abortifacient: Side effects include prostration, vomiting and diarrhea.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Difficult to breed mares / Controlling time of estrus | 1 mg per 45 kg body weight IM | IM | once | once | π NA |
| Luteolysis and to stimulate uterine contractions | 10 mg (total dose) IM once | IM | once | once | π NA |
| Abortifacient (Prior to 12th day of pregnancy) | 5 mg IM | IM | once | once | π NA |
| Abortifacient (After 4th month of pregnancy) | 1 mg per 45 kg body weight (1 mg per 100 pounds) daily until abortion takes place | IM | once daily | until abortion | π NA |
| Abortifacient (From day 80-300) | 2.5 mg q12h | IM | q12h | approx 4 injections on average | π NA |
| Estrus synchronization (Two injection method) | 5 mg dinoprost IM on day 1 and again on day 16 | IM | day 1 and day 16 | 16 days | π NA |
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Estrus synchronization | 25 mg IM either once or twice at a 10-12 day interval | IM | once or twice | 10-12 day interval | π NA |
| Unobserved (silent) estrus | 25 mg IM | IM | once | once | π NA |
| Pyometra | 25 mg IM twice, 8 hours apart | IM | twice, 8 hours apart | 1 day | π NA |
| Abortifacient (5-150 days of gestation) | 25-30 mg IM | IM | once | once | π NA |
| Abortifacient (After 150 days of gestation) | 25 mg dexamethasone with 25 mg dinoprost | IM | once | once | π NA |
| Induce parturition | 25-30 mg IM | IM | once | once | π NA |
- Pyometra: Alternatively, 25 mg IM once (McCormack 1986).
- Abortifacient (5-150 days of gestation): Alternatively, 25 mg IM during first 100 days.
- Induce parturition: Delivery will occur in about 72 hours.
Swine
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Estrus synchronization (grouping) | 15 mg dinoprost IM, followed in 12 hours by 10 mg IM | IM | twice, 12 hours apart | 1 day | π NA |
| Abortifacient | 5-10 mg IM | IM | once | once | π NA |
| Induce parturition | 10-25 mg IM from 2-6 days before expected parturition | IM | once | once | π NA |
- Estrus synchronization (grouping): At 15-55 days of gestation.
- Abortifacient: Abortion occurs in 24-48 hours.
- Induce parturition: Farrowing usually occurs 24-36 hours later.
Sheep
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Estrus synchronization | 8 mg IM on day 5 of estrous cycle and repeat in 11 days | IM | twice, 11 days apart | 11 days | π NA |
| Abortifacient (first two months of pregnancy) | 10-15 mg IM | IM | once | once | π NA |
- Abortifacient (first two months of pregnancy): Abortion takes place within 72 hours.
Goats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Estrus synchronization | 8 mg IM on day 4 of estrous cycle and repeat in 11 days | IM | twice, 11 days apart | 11 days | π NA |
| Pseudopregnancy (hydrometra/mucometra) | 5 mg IM once | IM | once | once | π NA |
| Abortifacient | 5-10 mg IM throughout entire pregnancy | IM | once | once | π NA |
| Induce parturition | 2.5-20 mg on days 144-149 | IM | once | once | π NA |
- Abortifacient: Abortion takes place in 4-5 days.
- Induce parturition: Higher dosage (20 mg) yields more predictable interval to delivery.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Dinoprost tromethamine is the tromethamine (THAM) salt of the naturally occurring βprostaglandin F2alpha (PGF2Ξ±)β. It is widely used in veterinary reproductive medicine across multiple species.
- Large Animals: Primarily used as a luteolytic agent for estrous synchronization, treatment of unobserved (silent) estrus, pyometra, and as an abortifacient or parturition-inducing agent in cattle, horses, swine, and small ruminants.
- Small Animals: Used off-label as an abortifacient and as an adjunctive medical therapy for open-cervix pyometra in dogs and cats.
Clinical Pearl: Dinoprost has a very narrow therapeutic index in dogs. The LD50 is only about 5 times the recommended therapeutic dose, making accurate dosing and careful monitoring critical. Newer protocols for pyometra often favor aglepristone combined with cloprostenol or misoprostol due to a better safety profile.
Mechanism of action
Dinoprost acts directly as a βprostaglandin F2alpha (PGF2Ξ±)β analog.
- Luteolysis: Binds to specific PGF2Ξ± receptors on the corpus luteum β inhibits steroidogenesis β induces structural and functional regression of the corpus luteum (luteolysis) β rapid decline in serum progesterone levels.
- Myometrial Contraction: Directly stimulates myometrial smooth muscle activity β increases intracellular calcium β induces strong uterine contractions.
- Cervical Relaxation: Promotes relaxation and dilation of the cervix, facilitating the expulsion of uterine contents (fetus or purulent material in pyometra).
Safety & warnings
Contraindications
- Pregnancy (unless abortion or induced parturition is desired)
- Intravenous (IV) administration
- Animals with bronchoconstrictive respiratory disease (e.g., asthma, 'heaves' in horses)
- Mares with acute or subacute disorders of the vascular system, GI tract, respiratory system, or reproductive tract
- Camelids (associated with acute toxicity and death)
- Relative contraindication: Closed-cervix pyometra
- Extreme caution in elderly (>8 years old) or debilitated animals, or those with severe cardiopulmonary, renal, or hepatic disease
Adverse effects
- Dogs/Cats: Abdominal pain, emesis, defecation, urination, pupillary dilation followed by constriction, tachycardias, restlessness, anxiety, fever, hypersalivation, dyspnea, panting. Fatalities are possible (especially in dogs). Cats may exhibit intense grooming and vocalization.
- Cattle: Infection at injection site, salivation, hyperthermia (especially at higher doses).
- Swine: Erythema, pruritus, urination, defecation, slight ataxia, hyperpnea, dyspnea, nesting behavior, abdominal muscle spasms, tail movements, increased vocalization, salivation.
- Horses: Transient decreased body temperature, sweating. Less frequently: increased respiratory and heart rates, ataxia, abdominal pain, lying down.
Precautions
HUMAN SAFETY WARNING: Pregnant women, asthmatics, and women of childbearing age should handle this product with extreme caution. Accidental skin exposure should be washed off immediately with soap and water.
VETERINARY PRECAUTIONS:
- Do NOT administer intravenously (IV).
- Use with extreme caution in dogs and cats over 8 years of age or those with significant concurrent illness.
- Monitor small animals closely for severe cardiorespiratory effects after administration.
- Closed-cervix pyometra is considered a relative contraindication due to the risk of uterine rupture from induced contractions.
Drug interactions
Activity may be enhanced by dinoprost.
Reduced effect of dinoprost would be expected with concomitant administration.
Monitoring
- Cardiorespiratory effects (especially in dogs and cats, particularly after higher dosages)
- Adverse effects (vomiting, diarrhea, hyperthermia, distress)
- Efficacy of treatment (e.g., ultrasound for pyometra resolution or pregnancy termination, observation for estrus)
Pharmacokinetics
Half-life
Absorption
Distributes very rapidly to tissues after injection.
Distribution
Rapidly distributed to tissues.
Overdose
Dogs are highly sensitive to the toxic effects of dinoprost. The LD50 in the bitch is reported to be 5.13 mg/kg SC, which is only about 5 times greater than the recommended dose used by some clinicians.
In large animals (cattle, swine, horses), overdose quantities (e.g., 5-10X recommended doses) result in exaggerated adverse effects such as hyperthermia, vomiting, and severe abdominal cramping.
Treatment: If clinical signs are severe in any species, immediate supportive and symptomatic therapy is recommended.
Available products
Formulations
- Injection: 5 mg/mL (as dinoprost) in 10 mL and 30 mL vials
Veterinary
- Dinoprost Tromethamine for injection, equivalent to 5 mg/mL of dinoprost in 10 mL and 30 mL vials (Lutalyse Sterile Solution, Amtech Prostamate, In-Synch, Prostamate)
Regulatory status
No regulatory data for: πΊπΈ US Β· πͺπΊ EU Β· π¬π§ UK Β· ππ° HK Β· πΉπΌ TW Β· π―π΅ JP Β· π°π· KR Β· π¦πΊ AU
Storage & stability
Store at room temperature (15-30Β°C) in airtight containers. Dinoprost is considered to be relatively insensitive to heat, light, and alkalis.
Client information
CRITICAL HUMAN SAFETY WARNING: Pregnant women, asthmatics, or persons with bronchial diseases must handle this product with extreme caution. Any accidental exposure to the skin should be washed off immediately with soap and water.
- This medication is used to manage reproductive conditions (such as uterine infections/pyometra) or to terminate an unwanted pregnancy.
- In dogs and cats, expect to see side effects shortly after the injection (usually within 5 to 15 minutes). These may include panting, drooling, vomiting, diarrhea, urination, and restlessness.
- While these side effects can be distressing to watch, they typically pass within 20 to 30 minutes. Keep your pet in a comfortable, easy-to-clean area during this time.
- If your pet experiences severe difficulty breathing, extreme lethargy, or if side effects persist, contact your veterinarian immediately.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturerβs current label.