Cabergoline
Cabergoline is a long-acting dopamine D2 receptor agonist used clinically for hyperprolactinaemia and Parkinson's disease. In the PED context it is used to lower prolactin elevated by 19-nortestosterone compounds (nandrolone, trenbolone), addressing prolactin-driven gynaecomastia and sexual dysfunction. Its long half-life allows twice-weekly dosing, but high cumulative doses carry a cardiac valve risk.
01 Overview
Cabergoline suppresses prolactin release from the pituitary by stimulating dopamine D2 receptors, and its very long half-life means twice-weekly dosing controls prolactin steadily. Users of 19-nor compounds may develop elevated prolactin with associated erectile dysfunction, low libido and lactation-type symptoms, and cabergoline is the more convenient of the dopamine agonists for this.
The key safety concern derives from Parkinson's practice: high daily doses of ergot dopamine agonists were linked to cardiac valve fibrosis. The doses used to control prolactin in this context are far lower, but the association is why cabergoline is dosed to the minimum effective amount and why some prefer pramipexole. Nausea, hypotension and mood effects also occur.
02 Mechanism
Long-acting ergot-derived dopamine D2 receptor agonist that inhibits pituitary prolactin secretion.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Prolactin control | 0.25–0.5 mg/wk | Oral | Typically 0.25 mg twice weekly; titrate to prolactin. Keep to the minimum effective dose. |
| Hyperprolactinaemia (label) | 0.5–1 mg/wk | Oral | Clinical range up to ~1 mg/week in divided doses; higher chronic doses raise valve risk. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Lowered prolactinEffectively suppresses elevated prolactin, resolving prolactin-driven sexual dysfunction and lactation symptoms. | normalises prolactin | Clinical | |
| Improved libido/erectile functionRestores sexual function where dysfunction is caused by hyperprolactinaemia. | when prolactin-driven | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Cardiac valve fibrosis (high dose)Ergot dopamine agonists at high cumulative doses are associated with valvular heart disease. | Severe | Rare at low doses | Clinical | |
| NauseaNausea, especially early in treatment. | Mild | Common | Clinical | |
| Orthostatic hypotension / dizzinessLight-headedness and low blood pressure, particularly at initiation. | Mild | Common | Clinical |