Cabergoline is an ergot-derived dopamine agonist that lowers prolactin, the pituitary hormone that drives milk production. In the US it is approved only for hyperprolactinemia (too much prolactin), whether idiopathic or caused by a pituitary adenoma. It was first approved in 1996 as Pfizer’s Dostinex and is now sold as generic 0.5 mg tablets.

Outside medicine, cabergoline is used by some anabolic steroid users who believe it prevents “prolactin” side effects such as gynecomastia or low libido. No controlled human trial has tested it for that purpose. Its main serious risk is fibrosis of the heart valves and other tissues, which is why the label requires an echocardiogram before treatment starts.

This page summarizes what the FDA label, the UK product information and clinical studies report. It is for education only and is not medical advice.

Property	Detail
Drug class	Ergot derivative; dopamine D2 receptor agonist (prolactin inhibitor)
Brands / approval	Dostinex (Pfizer), NDA 020664, approved December 23, 1996; brand now discontinued in the US; generics available
Route	Oral tablet
Strength	0.5 mg scored tablet
Labeled US dose	0.25 mg twice weekly to start; maximum 1 mg twice weekly
Half-life (label)	63–69 h in healthy volunteers; 79–115 h in patients with hyperprolactinemia (UK label)
Key mechanism fact	High affinity for D2 receptors; also an agonist at the serotonin 5-HT2B receptor, which is linked to valve fibrosis
US status	Prescription only; not a controlled substance (DEA schedule: none)

What it is

Cabergoline’s chemical name is 1-[(6-allylergolin-8β-yl)-carbonyl]-1-[3-(dimethylamino)propyl]-3-ethylurea: formula C₂₆H₃₇N₅O₂, molecular weight 451.6 g/mol (FDA label; PubChem). It belongs to the ergoline family, the same chemical class as bromocriptine and pergolide.

Dopamine released from the hypothalamus normally keeps prolactin secretion in check. Cabergoline mimics that signal by stimulating D2 receptors on the pituitary’s prolactin-producing cells (lactotrophs). The US label reports low affinity for D1, α-adrenergic and 5-HT1/5-HT2 serotonin receptors. The UK label adds that cabergoline is an agonist at the 5-HT2B serotonin receptor, the receptor tied to drug-induced valve disease (Dostinex SmPC).

The UK label also states that, apart from lowering prolactin and blood pressure, cabergoline had no effect on basal secretion of other pituitary hormones or cortisol in human studies.

Pharmacokinetics

From the US and UK labels:

Parameter	Value
Time to peak plasma level	2–3 h after 0.5–1.5 mg
Dose proportionality	Plasma levels roughly proportional across 0.5–7 mg
Effect of food	High-fat food did not change exposure
Protein binding	40–42%
Elimination half-life	63–69 h (12 healthy volunteers, urinary data); 79–115 h in hyperprolactinemic patients
Time to steady state	About 4 weeks (UK label)
Excretion (radiolabeled dose)	≈ 60% in feces and ≈ 22% in urine over 20 days; under 4% unchanged in urine
Metabolism	Extensive hydrolysis of the urea side chain; metabolites do not lower prolactin

The effect lasts much longer than plasma levels suggest. After a single 0.3–1.5 mg dose, prolactin falls within 3 hours and stays suppressed for 7–28 days in healthy volunteers and hyperprolactinemic patients, according to the UK label. This long action is why the drug is taken only once or twice a week.

In a dose-ranging study, 12 healthy men took single doses of 0.5, 1.0 and 1.5 mg (Andreotti et al., JCEM 1995):

every dose fully suppressed prolactin in every subject;
suppression came sooner and lasted longer at 1.0 and 1.5 mg, with no significant difference between those two doses;
blood pressure fell progressively, and one man had symptomatic low blood pressure after 1.0 mg and could not take the 1.5 mg dose.

Liver disease raises exposure. Mean cabergoline AUC (total exposure) was 1.5-fold higher in moderate (Child-Pugh B) and 5.6-fold higher in severe (Child-Pugh C) hepatic impairment, each in only 4 patients. The US label advises against use in severe hepatic impairment. Kidney impairment did not change the pharmacokinetics.

Approved medical use

United States

The current US label (revised 2025) covers one indication: hyperprolactinemic disorders in adults, either idiopathic or due to pituitary adenomas (FDA label).

Step	Labeled instruction
Before starting	Evaluate for valvular heart disease, including an echocardiogram; do not give if valve disease is found
Starting dose	0.25 mg twice weekly, with or without food
Titration	Increase by 0.25 mg twice weekly, no more often than every 4 weeks, until prolactin is normal
Maximum dose	1 mg twice weekly
After stopping	Check prolactin periodically to decide whether to restart

The label says to avoid cabergoline for suppressing postpartum lactation in the US. It cites serious events, including hypertension, stroke, heart attack, seizures and death, seen when bromocriptine, another dopamine agonist, was used that way. The label also states that cabergoline is not approved for Parkinson’s disease and that durability of effect beyond 24 months has not been established.

Outside the US

In the UK, Dostinex is also licensed to stop lactation after delivery, stillbirth or abortion (Dostinex SmPC):

preventing lactation: a single 1 mg dose on the first day after delivery;
suppressing established lactation: 0.25 mg every 12 hours for 2 days (1 mg total);
hyperprolactinemia: usually 1 mg per week, ranging from 0.25 to 2 mg per week, with a ceiling of 3 mg per day.

In 2008 the European Medicines Agency reviewed the ergot-derived dopamine agonists, which in Europe are mainly used for Parkinson’s disease. For cabergoline it required echocardiographic monitoring before and during treatment, cut the maximum dose to 3 mg per day, and listed cardiac fibrosis as a very common side effect (EMA, 2008).

What the research shows

Hyperprolactinemia: dose response

The US label’s placebo-controlled study (Study 1) randomized 188 women with hyperprolactinemia to placebo or one of several twice-weekly doses for 4 weeks. The endpoint was a normal prolactin level (under 20 ng/mL, the upper reference limit):

Arm (twice weekly, weeks 2–4)	n	Normal prolactin at 4 weeks
Placebo	20	0%
0.5 mg	42	76%
0.75 mg	42	74%
1 mg	42	95%

A lower-dose arm (0.125 mg twice weekly) was not effective and is not reported in the label.

Hyperprolactinemia: head to head with bromocriptine

The pivotal comparison randomized 459 women with hyperprolactinemic amenorrhea (absent periods) to cabergoline 0.5–1.0 mg twice weekly or bromocriptine 2.5–5.0 mg twice daily. Treatment was double-blind for 8 weeks and then open-label to 24 weeks (Webster et al., NEJM 1994):

Outcome	Cabergoline (n = 223)	Bromocriptine (n = 236)
Stable normal prolactin	83%	59% (p under 0.001)
Ovulatory cycles or pregnancy	72%	52% (p under 0.001)
Amenorrhea persisting	7%	16%
Any adverse effect	68%	78% (p = 0.03)
Stopped because of side effects	3%	12% (p under 0.001)

Gastrointestinal side effects were less frequent, milder and shorter-lived on cabergoline. In the label’s 8-week double-blind data from the same program, nausea occurred in 29% on cabergoline vs 43% on bromocriptine.

Stopping treatment

Hyperprolactinemia often returns after the drug is stopped.

Prospective cohort. In 200 patients who met strict criteria for withdrawal (normal prolactin, and no tumor or a much smaller one on MRI), recurrence 2–5 years later was 24% for non-tumoral hyperprolactinemia, 31% for microprolactinomas and 36% for macroprolactinomas. No tumor regrew (Colao et al., NEJM 2003).
Meta-analysis. Across 19 studies and 743 patients, only 21% (95% CI 14–30%) stayed normal after a dopamine agonist was withdrawn. Success was most likely when cabergoline had been used for at least 2 years (Dekkers et al., JCEM 2010).

Lactation inhibition

A double-blind European trial randomized 272 women who did not wish to breastfeed. They received either a single 1 mg dose of cabergoline or bromocriptine 2.5 mg twice daily for 14 days (European Multicentre Study Group, BMJ 1991):

Outcome	Cabergoline 1 mg once	Bromocriptine for 14 days
Complete success	106 of 136 (78%)	94 of 136 (69%)
Partial success	21 of 136	33 of 136
Rebound breast symptoms by day 15 (among complete successes)	5	23 (p under 0.0001)

This use is licensed in the UK but, as noted above, the US label says to avoid it.

Sexual function in men

Prolactin rises after orgasm, and chronically high prolactin is known to reduce sexual drive. Two small studies have tested cabergoline on sexual function directly:

Single dose in healthy men. In a single-blind, placebo-controlled crossover study of 10 men, 0.5 mg cabergoline lowered prolactin and increased measures of sexual drive, function and the perceived quality of the refractory period. Raising prolactin with another drug (protirelin) at the same time abolished the effect (Krüger et al., J Endocrinol 2003).
Psychogenic erectile dysfunction. A 4-month double-blind trial randomized 50 men to cabergoline or placebo. Erectile function, desire, orgasmic function and satisfaction improved on cabergoline (Nickel et al., Int J Impot Res 2007).

Both studies are small, and neither establishes cabergoline as a treatment for sexual dysfunction. It is not approved for that use. “Increased libido” appears in the US label among uncommon trial side effects, and hypersexuality appears among postmarketing impulse-control reports (see below).

Use alongside anabolic steroids

About “prolactin gyno.” Cabergoline is often described online as a gynecomastia treatment for users of nandrolone or trenbolone. We found no controlled human trial of cabergoline for preventing or treating gynecomastia, or for any outcome in anabolic steroid users. Cabergoline is not a SERM and does not block estrogen; its documented action is on dopamine receptors.

The human data on prolactin in steroid users are thin. One cross-sectional study of 60 gym-goers in Baghdad found higher prolactin in the 30 who used anabolic steroids (including testosterone, boldenone and nandrolone) than in 30 non-users (Qasim Ali et al., Steroids 2024). The design cannot show which compound was responsible or whether the rise caused any symptoms.

Side effects and risks

Heart valve disease and fibrosis

This is the most serious risk. The US label contraindicates cabergoline in anyone with a history of valve disease or pericardial fibrosis, and requires an echocardiogram before treatment and every 6–12 months during it. The risk is clearest at the high doses once used for Parkinson’s disease, usually over 2 mg per day according to the label.

Study	Population	Finding
Zanettini et al., NEJM 2007	Echocardiography in Parkinson’s patients: 49 on cabergoline, 90 controls	Moderate-to-severe regurgitation in any valve: 28.6% vs 5.6%; higher in those with greater cumulative dose
Schade et al., NEJM 2007	UK nested case-control, 11,417 users of Parkinson’s drugs	Current cabergoline use: incidence-rate ratio 4.9 (95% CI 1.5–15.6) for new valve regurgitation
US label	12-year multi-country cohort, Parkinson’s disease	Valve regurgitation per 10,000 person-years: 68 on cabergoline vs 10 on non-ergot agonists and 11 on levodopa
Trifirò et al., Drug Saf 2012	Hyperprolactinemia cohort, 6,740 dopamine agonist users	No association with ergot agonist use: OR 0.47 (95% CI 0.20–1.19)
Stiles et al., JCEM 2019	Meta-analysis of 13 studies, hyperprolactinemia doses for ≥ 6 months	More tricuspid regurgitation: OR 3.74 (95% CI 1.79–7.8); no increase in other valve lesions; no symptomatic cases

So the evidence for harm at hyperprolactinemia doses is weaker than at Parkinson’s doses, but not absent. The UK label states that valve disease is associated with cumulative dose and that the lowest effective dose should be used. The UK label ties these fibrotic reactions to ergot derivatives that act on the 5-HT2B receptor, such as cabergoline.

The label also describes postmarketing cases of pleural, pulmonary and retroperitoneal fibrosis (scarring in the chest lining, lungs or the back of the abdomen). Warning signs include shortness of breath, persistent cough, chest pain, flank pain and leg swelling. Pulmonary symptoms improved in patients who stopped the drug.

Common side effects

In the US label’s 4-week placebo-controlled trial (168 women on cabergoline, 20 on placebo):

Side effect	Cabergoline	Placebo
Nausea	27%	20%
Headache	26%	25%
Dizziness	15%	5%
Constipation	10%	0%
Fatigue	7%	0%
Postural hypotension	4%	0%

Orthostatic hypotension (a blood pressure drop on standing) is more likely with other blood-pressure-lowering drugs. The UK label also warns of somnolence and, rarely, sudden sleep onset.

Impulse control disorders

Drugs that increase dopamine signaling can trigger compulsive gambling, spending, eating or sexual behavior. The US label tells prescribers to ask about these specifically, because patients may not recognize them. Studies in hyperprolactinemia patients suggest the risk is concentrated in men:

In a Mayo Clinic survey, men with prolactinomas treated with dopamine agonists reported any impulse control disorder in 27.7%, compared with 3.7% of men with non-functioning pituitary tumors who had not taken them (Bancos et al., Clin Endocrinol 2014).
In a multicenter study of 113 treated patients and 99 controls, hypersexuality screened positive in 22.1% vs 8.1%. Male sex (OR 13.85) was the strongest independent risk factor for hypersexuality (De Sousa et al., JCEM 2020).

Interactions

Dopamine antagonists: phenothiazines, butyrophenones, thioxanthenes and metoclopramide oppose cabergoline’s effect; the US label does not recommend combining them.
Macrolide antibiotics: the UK label says not to combine cabergoline with drugs such as erythromycin, which raise its systemic exposure.
Other ergot alkaloids: not recommended during long-term treatment (UK label).
Other drugs linked to valve disease: use only if the benefit outweighs the risk (US label).
Antihypertensives: add to the risk of orthostatic hypotension.

Who should not take it

From the US label:

uncontrolled hypertension;
known hypersensitivity to ergot derivatives;
a history of heart valve disease or pericardial fibrosis;
a history of pleural, pulmonary or retroperitoneal fibrosis.

The UK label adds hepatic insufficiency, toxemia of pregnancy, concurrent antipsychotic use and a history of postpartum psychosis. Because of the long half-life, it advises women planning pregnancy to stop cabergoline one month before trying to conceive.

Monitoring

What	When (US label unless noted)
Echocardiogram	Before starting; then every 6–12 months, or sooner with a new murmur, swelling, breathlessness or heart failure
Blood pressure, including on standing	Baseline and during treatment
Prolactin	Every 4 weeks while titrating (patient labeling), then periodically, including after stopping
ESR, creatinine, chest X-ray	Consider at baseline and as needed to detect fibrosis
New compulsive urges	Ask at every visit

Key takeaways

A long-acting prolactin lowerer. Cabergoline stimulates pituitary D2 receptors, suppresses prolactin within hours, and keeps it down for days to weeks after a single dose.
One US indication. It is approved for hyperprolactinemia at 0.25–1 mg twice weekly. The US label says to avoid it for stopping postpartum lactation, though the UK licenses that use.
Better tolerated than bromocriptine. In 459 women, it normalized prolactin in 83% vs 59% and caused fewer treatment-stopping side effects (3% vs 12%).
Valve fibrosis is the key risk. It is well documented at Parkinson’s doses. At hyperprolactinemia doses, a meta-analysis found more tricuspid regurgitation without symptomatic disease, and the label still requires echocardiograms.
Watch for compulsive behavior. Hypersexuality and other impulse control problems are more common in treated men than in controls.
No evidence for “prolactin gyno.” No controlled human trial supports cabergoline for preventing or treating gynecomastia in anabolic steroid users.

Sources

Teva Pharmaceuticals USA. Cabergoline tablets, prescribing information (revised 2025). DailyMed.
Food and Drug Administration. Drugs@FDA: Dostinex (cabergoline), NDA 020664. FDA.
Pfizer Ltd. Dostinex 0.5 mg tablets, summary of product characteristics. Electronic Medicines Compendium. emc.
National Center for Biotechnology Information. Cabergoline, PubChem CID 54746. PubChem.
European Medicines Agency. EMEA recommends new warnings and contraindications for ergot-derived dopamine agonists. Press release, June 26, 2008. EMA.
Andreotti AC, Pianezzola E, Persiani S, et al. Pharmacokinetics, pharmacodynamics, and tolerability of cabergoline, a prolactin-lowering drug, after administration of increasing oral doses (0.5, 1.0, and 1.5 milligrams) in healthy male volunteers. J Clin Endocrinol Metab. 1995;80(3):841–845. PubMed.
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European Multicentre Study Group for Cabergoline in Lactation Inhibition. Single dose cabergoline versus bromocriptine in inhibition of puerperal lactation: randomised, double blind, multicentre study. BMJ. 1991;302(6789):1367–1371. PubMed.
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Cabergoline