Metergoline
Benzyl (8S,10S)-(1,6-dimethylergolin-8-ylmethyl)carbamate
Also known as: Contralac · Liserdol · FI-6337 · MCE · Metergoliini · Metergolina · Métergoline · Metergolinum · Methergoline
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 |
|---|---|---|---|---|---|
| Treatment of pseudopregnancy | 0.5 mg/kg (500 micrograms/kg) PO twice a day | PO | q12h | 4-5 days | 🌎 NA |
| Treatment of pseudopregnancy | 0.1 mg/kg, PO twice a day | PO | q12h | 8 to 10 days | 🌎 NA |
| Treatment of pseudopregnancy | 0.1 mg/kg q12h PO with food | PO | q12h | 10 days | 🌎 NA |
| To induce estrus | 0.1 mg/kg PO twice a day | PO | q12h | From 100 days after ovulation until the following proestrus | 🌎 NA |
- Treatment of pseudopregnancy: Occasional failures can be dealt with by repeating the treatment protocol and extending it to 8 to 10 days, or by using joint protocols of cabergoline plus metergoline or cabergoline plus bromocriptine.
- Treatment of pseudopregnancy: Side effects were limited to hyperexcitation and nausea, did not lead to termination of therapy, and gradually dissipated during the second week.
- To induce estrus: Results have been variable depending on dosage. Can significantly shorten the interoestrous interval.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of pseudopregnancy or to halt post-partum lactation | 0.125 mg/kg PO twice a day | PO | q12h | 4-8 days | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Metergoline is an ergot-derivative medication primarily utilized in veterinary medicine to manage pseudopregnancy (false pregnancy) in dogs.
Key clinical points:
- Acts as a prolactin inhibitor to stop unwanted lactation and behavioral changes associated with false pregnancy.
- Has been investigated as an abortifacient at high doses (0.4-0.6 mg/kg) during the last 3 weeks of gestation.
- Not commercially available in the USA, but widely used as a veterinary product in several European and South American countries.
- In human medicine, it is used for hyperprolactinemia, prolactinomas, and migraine prophylaxis.
Mechanism of action
Metergoline reduces prolactin secretion primarily through its serotonin receptor antagonism.
Mechanistic pathway:
- Serotonin (5-HT) antagonism → Inhibition of prolactin release from the anterior pituitary.
- Unlike other prolactin inhibitors (e.g., cabergoline, bromocriptine), it possesses strong central and peripheral anti-serotonin effects.
- Exhibits weak direct dopamine-2 (D2) agonist effects and acts as an antagonist at dopamine-1 (D1) receptors.
Safety & warnings
Contraindications
- Pregnancy (unless abortion is desired)
- Nursing mothers
- Hypersensitivity to ergot derivatives
Adverse effects
- Anxiety
- Aggressiveness
- Depression
- Hyperexcitation
- Whining
- Escaping behavior
- Anorexia
- Vomiting
- Nausea
Precautions
Use with caution in patients with significantly impaired liver function; a lower dosage may be required. Patients that do not tolerate cabergoline or bromocriptine may or may not tolerate metergoline. Do not use in pregnant animals unless pregnancy termination is the specific clinical goal.
Drug interactions
May cause additive effects if used with metergoline
May cause additive effects if used with metergoline
May cause additive effects if used with metergoline
Use with metergoline may reduce the efficacy of both drugs and should be avoided
Potentially could reduce the efficacy of each drug
Monitoring
- Clinical efficacy (resolution of pseudopregnancy signs)
- Adverse behavioral or GI effects
- Liver function tests (if used long-term)
Pharmacokinetics
Half-life
Absorption
In humans, oral bioavailability is about 25%.
Distribution
In humans, volume of distribution is 0.8 L/kg.
Metabolism
Metabolized in the liver to at least one active metabolite (1-desmethylmetergoline) which attains plasma levels higher than that of the parent drug.
Elimination
In humans, elimination half-life of the parent drug is about 50 minutes; 1-desmethylmetergoline is 80-100 minutes.
Overdose
Little information is available regarding acute toxicity. Vomiting is the most likely clinical sign expected in an overdose situation. Treatment should be supportive and symptomatic.
Available products
Formulations
- Oral tablets
Veterinary
- Metergoline 0.5 mg oral tablets
- Metergoline 2 mg oral tablets
Human-labeled
- Metergoline 4 mg tablets
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Metergoline tablets should be stored at room temperature; protected from light.
Client information
Important: Give this medication with food to help reduce stomach upset.
- Watch for side effects: Your pet may experience nausea, vomiting, or changes in behavior (such as anxiety, whining, or escaping behavior). Contact your veterinarian if vomiting persists or behavioral changes are severe.
- Do not give to pregnant pets: This medication can cause abortion.
- Keep this and all medications securely out of reach of children and other pets.
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.