Cabergoline (Dostinex) - Dopamine D2 Agonist for Prolactin Control — Anabolic Steroids
Long-acting dopamine D2 receptor agonist FDA-approved for hyperprolactinemia, used in bodybuilding to control prolactin elevation from 19-nor compounds (nandrolone, trenbolone), with superior tolerability to bromocriptine.
Overview
Cabergoline (Dostinex) is a long-acting ergot-derived dopamine D2 receptor agonist FDA-approved for the treatment of hyperprolactinemia and prolactin-secreting pituitary adenomas (prolactinomas). It has largely replaced bromocriptine as first-line therapy due to superior efficacy, tolerability, and convenient twice-weekly dosing. A landmark comparative trial demonstrated that cabergoline normalized prolactin levels in 83% of patients vs 59% for bromocriptine, with significantly fewer side effects (PMID: 8013789). Cabergoline can also shrink macroprolactinomas by >50% in approximately 80% of cases. In the bodybuilding community, cabergoline is used to manage prolactin elevation caused by 19-nortestosterone derivatives (nandrolone/deca-durabolin and trenbolone), which can activate prolactin secretion via progestational mechanisms. Elevated prolactin causes sexual dysfunction (erectile dysfunction, anorgasmia), gynecomastia, galactorrhea, and mood disturbances. Cabergoline is also notable for its association with decreased refractory period and enhanced libido via dopaminergic mechanisms. High cumulative doses have been associated with cardiac valvulopathy in Parkinson's disease patients, though this is rarely relevant at endocrine doses. PMID: 8013789, 16728537, 24614561.
Indications
- Hyperprolactinemia and prolactin-secreting pituitary adenomas (prolactinomas) - FDA-approved
- Prolactin management during 19-nor anabolic steroid use (nandrolone, trenbolone) - off-label, bodybuilding
- Dopaminergic sexual enhancement and refractory period reduction (off-label)
- Ovulation induction in hyperprolactinemic infertility (off-label; restoring normal prolactin enables ovulation)
Mechanism of Action
Cabergoline binds D2 dopamine receptors on anterior pituitary lactotroph cells, mimicking dopamine's tonic inhibitory effect on prolactin gene transcription and secretion
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Cabergoline (Dostinex) | 0.25 mg | Twice weekly | Starting dose for hyperprolactinemia; also standard bodybuilding prophylactic dose during 19-nor cycles |
| Cabergoline | 0.5 mg | Twice weekly | Standard therapeutic dose for prolactinoma; effective in normalizing prolactin in majority of patients |
| Cabergoline | 1.0 mg | Twice weekly (2mg/week total) | Higher dose for resistant prolactinomas; maximum typically 2mg/week; cardiac monitoring if prolonged |
| Cabergoline | 0.25 mg | Once weekly (PRN) | Minimal effective dose for mild prolactin elevation; or as-needed for dopaminergic sexual enhancement |
Safety & Contraindications
- Nausea, headache, and dizziness are most common side effects (15-25%); usually mild and transient with low-dose endocrine use
- Orthostatic hypotension: first-dose phenomenon; start with bedtime dosing and low dose; caution in patients on antihypertensives
- Cardiac valvulopathy: associated with high cumulative doses used in Parkinson's disease (3-7mg/day); risk is minimal at endocrine doses (0.25-1mg/week) but echocardiographic monitoring recommended if chronic use
- Impulse control disorders: pathological gambling, hypersexuality, compulsive shopping reported (dopaminergic class effect); educate patients
- Contraindicated with uncontrolled hypertension and hypersensitivity to ergot derivatives
- May cause fibrosis (retroperitoneal, pulmonary, pericardial) at high doses; monitor for dyspnea, flank pain