Dinoprost
Dinoprost tromethamine (Prostaglandin F2 alpha)
Also known as: Enzaprost · Lutalyse · Prostaglandin F2 alpha · PGF2a · Dinoprostum · Dinoprost tromethamine
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
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Open pyometra | 0.1-0.25 mg/kg | SC | q12h | until the uterus is empty; usually 3-5 days treatment required | 🌍 EU |
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Open pyometra / Uterine contraction | 0.1 or 0.25 mg/kg | SC | q12-24h | — | 🌍 EU |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Dinoprost tromethamine is a synthetic analogue of Prostaglandin F2 alpha (PGF2α). In veterinary medicine, it is primarily used for its ecbolic effects to stimulate uterine contractions and induce cervical relaxation, making it a key medical treatment for open pyometra.
WARNING: Pregnant women and asthmatics should strictly avoid handling this medication due to the risk of inducing bronchospasm or miscarriage.
Clinical Pearl: While the primary indication listed for small animals is open pyometra, PGF2α is also widely used for luteolysis (corpus luteum regression) in large animals and occasionally for pregnancy termination in small animals.
Mechanism of action
Dinoprost acts directly on the myometrium and corpus luteum.
- Binds to specific FP receptors on smooth muscle cells.
- → Increases intracellular calcium concentrations.
- → Induces strong, rhythmic uterine contractions.
- → Concurrently causes cervical relaxation to allow expulsion of uterine contents.
- → Induces luteolysis (regression of the corpus luteum), leading to a rapid drop in progesterone levels.
Safety & warnings
Contraindications
- Closed pyometra (due to severe risk of uterine rupture)
- Pregnancy (unless abortion is the intended outcome)
- Patients with respiratory disease/asthma (due to bronchoconstriction risk)
Adverse effects
- Hypersalivation (drooling)
- Panting
- Tachycardia
- Vomiting
- Urination
- Defecation
- Transient hyperthermia
- Locomotor incoordination
- Mild CNS signs
Precautions
Human Safety Warning: Pregnant women, asthmatics, and individuals with bronchial or other respiratory problems should strictly avoid handling this agent. Accidental spillage on the skin should be washed off immediately with soap and water to prevent transdermal absorption.
- Side effects are very common but typically diminish within 30 minutes of drug administration.
- There is no adverse effect on future fertility.
Monitoring
- Resolution of pyometra (via ultrasound and monitoring of vaginal discharge)
- Heart rate and respiratory rate post-injection
- Signs of excessive distress or hyperthermia
Pharmacokinetics
Half-life
Absorption
Rapidly absorbed following subcutaneous or intramuscular injection.
Distribution
Widely distributed but rapidly cleared.
Metabolism
Rapidly metabolized, primarily in the lungs (first-pass effect), to inactive metabolites.
Elimination
Excreted primarily via the kidneys (urine) and feces.
Overdose
Overdosage can lead to an exaggeration of the expected side effects, including severe vomiting, diarrhea, profound tachycardia, hyperthermia, and severe panting. In cases of closed pyometra, excessive doses or any use can cause uterine rupture and subsequent fatal peritonitis. Treatment is largely supportive as the drug has a very short half-life.
Available products
Formulations
- Injectable: 5 mg/ml solution
Veterinary
- Enzaprost 5 mg/ml solution for injection
- Lutalyse 5 mg/ml solution for injection
Regulatory status
Primarily approved for large animals; used off-label in small animals.
POM-V classification in the UK/EU.
POM-V classification.
No regulatory data for: 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store according to manufacturer guidelines. Typically stored at room temperature (below 25°C). Protect from light.
Client information
Expected Side Effects: It is very common for pets to experience drooling, panting, rapid heart rate, vomiting, and diarrhea shortly after the injection. Duration: These effects usually start within minutes but are temporary and typically resolve completely within 30 minutes.
CRITICAL SAFETY WARNING: If you are administering this medication at home, pregnant women and people with asthma must NOT handle this medication. Accidental exposure can cause miscarriage or severe asthma attacks. Wash hands thoroughly after handling.
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.