Bromocriptine
Bromocriptine mesylate
Also known as: Parlodel · Cycloset · bromocryptine · 2-bromergocryptine · bromocriptine methanesulphonate · bromocriptini mesilas · 2-bromo-alpha-ergocryptine mesylate · 2bromoergocryptine monomethanesulfonate · CB-154
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidencePseudocyesis (pseudopregnancy) | suppression of lactation (extra-label)
- q8-12h
NA
Governing clinical context (2)
- ■ Vomiting, fatigue, and low blood pressure are possible. For dogs and cats, giving this medicine with food may help to decrease vomiting.
- Protect tablets and capsules from light and store them in tight containers at 20°C to 25°C (68°F-77°F).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Bromocriptine is a semisynthetic ergot alkaloid derivative that acts as a dopamine agonist and prolactin inhibitor.
- Dogs: Used for pregnancy termination or pseudopregnancy (pseudocyesis). However, newer dopamine agonists like cabergoline are often preferred due to a much lower incidence of gastrointestinal side effects.
- Cats: Occasionally used as an adjunctive treatment for acromegaly to help reduce insulin requirements.
- Horses: Historically used for pituitary pars intermedia dysfunction (PPID/Equine Cushing's disease) or pituitary adenomas, though pergolide is the modern standard of care.
Clinical Pearl: Bromocriptine is notorious for causing significant emesis in dogs, which severely limits its clinical utility compared to cabergoline. Administering with food or using antiemetics may be required.
Mechanism of action
Bromocriptine acts primarily by stimulating postsynaptic dopamine (D2) receptors in the hypothalamus and anterior pituitary gland.
- Prolactin Inhibition: Dopamine receptor stimulation → release of prolactin-inhibitory factor (PIF) → direct inhibition of prolactin secretion from the anterior pituitary.
- Acromegaly: In certain pituitary adenomas, paradoxical suppression of growth hormone (GH) secretion occurs via dopaminergic stimulation.
- CNS Effects: Activates dopaminergic receptors in the neostriatum of the brain, which can influence motor control and behavior.
Safety & warnings
Contraindications
- Hypertension
- Pregnancy (in humans, documented teratogenicity not established but contraindicated)
- Nursing/lactating animals (interferes with lactation)
Adverse effects
- Nausea
- Vomiting (highly prevalent in dogs)
- Sedation
- Fatigue
- Hypotension
- Anorexia
- Depression
- Trembling
- Diarrhea
- Tachycardia
Precautions
Bromocriptine is generally contraindicated in patients with hypertension. It should be used with caution in patients with hepatic disease as metabolism of the drug may be reduced. Do not use in nursing animals as it interferes with lactation.
Drug interactions
May cause a disulfiram-type reaction
May increase prolactin concentrations; bromocriptine doses may need to be increased
May increase prolactin concentrations; bromocriptine doses may need to be increased
May increase prolactin concentrations; bromocriptine doses may need to be increased
May increase prolactin concentrations; bromocriptine doses may need to be increased
May elevate cyclosporine levels
May increase bromocriptine levels
May increase bromocriptine levels
May interfere with the effects of bromocriptine
Not recommended; concurrent use has caused severe hypertension and myocardial infarction in humans
May cause additive hypotension
Avoid use of bromocriptine with these compounds
May cause prolactin release in dogs, negating the effects of bromocriptine for treating pseudopregnancy
May increase bromocriptine levels
Enhanced bromocriptine effects reported in humans (rare), including ventricular tachycardia and cardiac dysfunction
Monitoring
- Clinical efficacy (dependent upon the reason for use)
- Blood pressure (especially if patients exhibit clinical signs associated with hypotension)
Pharmacokinetics
Absorption
In humans, only about 28% of a bromocriptine dose is absorbed from the gut. Due to a high first-pass effect, only about 6% reaches the systemic circulation.
Distribution
Distribution characteristics are not well described, but in humans, it is highly bound (90-96%) to serum albumin.
Metabolism
Metabolized by the liver to inactive and non-toxic metabolites.
Elimination
Eliminated primarily as metabolites.
Overdose
Overdosage may cause vomiting, severe nausea, and profound hypotension.
- Clinical Signs in Dogs: Common findings recorded in decreasing frequency include vomiting, trembling, diarrhea, subdued behavior, and tachycardia.
- Treatment: Standardized gut removal techniques should be employed when applicable, though emesis often occurs spontaneously. Institute cardiovascular monitoring (blood pressure, heart rate) and provide supportive care as needed.
Available products
Formulations
- Oral capsules
- Oral tablets
- Compounded injections (from oral dosage forms)
Human-labeled
- Bromocriptine Mesylate Oral Capsules: 5 mg (as base); Parlodel® (Novartis); generic
- Bromocriptine Mesylate Oral Tablets: 0.8 mg (as base); Cycloset® (Patheon); 2.5 mg; Parlodel® SnapTabs (Novartis); generic
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Tablets and capsules should be protected from light and stored in tight containers at temperatures less than 25°C.
Client information
- Give with food: Administering this medication with a meal can significantly reduce the chance of stomach upset and vomiting.
- Watch for nausea: Vomiting and loss of appetite are very common side effects, especially in dogs. Contact your veterinarian if these become severe.
- Lethargy: Your pet may seem unusually tired, subdued, or sedated.
- Do not use in nursing pets: This drug stops milk production.
Note: If your pet collapses, seems extremely weak, or has severe vomiting, seek veterinary care immediately, as this could indicate dangerously low blood pressure.
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.