Cabergoline
Cabergoline is a long-acting ergot-derived dopamine agonist that suppresses prolactin secretion. Its principal veterinary applications are canine pseudopregnancy and suppression of unwanted lactation. Additional reproductive uses depend on the stage-specific role of prolactin in ovarian and luteal function.
Cabergoline is generally more selective and longer acting than bromocriptine. Additional applications include selected anestrus, pregnancy-termination and avian reproductive protocols, with evidence and hormonal objectives differing among uses.
Group
Dopamine D2 agonist and prolactin inhibitor
Mechanism of Action
Cabergoline stimulates dopamine D2 receptors on anterior-pituitary lactotroph cells. These receptors provide an inhibitory signal to prolactin secretion, so agonist activity lowers circulating prolactin. The mechanism is dopamine agonism, not dopamine antagonism.
Lower prolactin reduces mammary development and milk production and can improve prolactin-associated signs of canine pseudopregnancy. In later canine gestation, where prolactin supports corpus-luteum function, suppression can reduce luteal support and contribute to pregnancy termination, often with an additional reproductive drug.
Effects on the reproductive endocrine axis can also shorten anestrus in selected bitches. Persistent receptor interaction and prolonged antiprolactin action help explain the duration of response. These prolactin-related effects do not establish reliable efficacy against every pituitary disorder or direct treatment of bacterial mastitis.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Pseudopregnancy | 5 mcg/kg | PO | Every 24 h | Up to 6 days; Initial course 4–6 days; may be repeated if needed. |
| Lactation suppression | 5 mcg/kg | PO | Every 24 h | Up to 5 days |
| Anestrus | 5 mcg/kg | PO | Every 24 h | Continue until 2 days after onset of proestrus. |
| Anestrus | 0.6 mcg/kg | PO | Every 24 h | Lower-dose alternative reported in one study. |
| Pseudopregnancy | 5 mcg/kg | PO | Every 24 h | Up to 10 days; Alternative course 5–10 days; repeat or extend according to response. |
| Pseudopregnancy | 5 mcg/kg | SC | Every 24–48 h | Requires an appropriate sterile compounded preparation, not the oral liquid. |
| Post-weaning mastitis lactation suppression | 5 mcg/kg | PO | Every 24 h | Adjunct after puppies have been weaned; treat mastitis separately as indicated. |
| Preoperative mammary-tumor management | Reference only | PO | Cabergoline 5 mcg/kg orally 5–7 days before surgery during diestrus is described; the excerpt does not explicitly specify a daily repeat interval. | |
| Pregnancy termination alone | Reference only | PO | After day 40, 5 mcg/kg orally for five days is described with only about 50% success; a daily interval is not independently stated in the dosage bullet. | |
| Pregnancy termination with cloprostenol | Reference only | PO | At 35–45 days: cabergoline 5 mcg/kg orally daily for seven days plus cloprostenol 1 mcg/kg SC on days 1 and 3. If not terminated by day 8, cabergoline may continue through day 12. Confirm completion. | |
| Pituitary-dependent hyperadrenocorticism | 100 mcg/kg | PO | Every 72 h | Limited historical study regimen; tumors above 5 mm did not respond. Not equivalent to routine prolactin-suppression dosing. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Prolactin suppression | 25–50 mcg/animal | PO | Queens: equivalent to 0.5–1 mL of 50 mcg/mL oral liquid; interval not assigned in the source. | |
| Preoperative mammary-tumor management | Reference only | PO | Cabergoline 5 mcg/kg orally 5–7 days before surgery during diestrus is described; the excerpt does not explicitly specify a daily repeat interval. | |
| Prolactin suppression | 5 mcg/kg | PO | Every 24 h | |
| Pregnancy termination with cloprostenol | Reference only | PO | Starting about day 30 after mating: cabergoline 5 mcg/kg orally daily plus cloprostenol 5 mcg/kg SC every 48 hours, with termination reported over 7–13 days. |
Birds
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Persistent egg laying | 10–20 mcg/kg | PO | Every 24 h | Psittacines; combine removal of breeding stimuli and light-cycle management. Optimal regimen remains uncertain. |
Indications
- Treatment of canine pseudopregnancy with clinically important mammary development, lactation or behavioral signs.
- Suppression of unwanted lactation, including selected post-weaning situations.
- Induction of estrous activity in selected bitches with primary or secondary anestrus.
- Selected pregnancy-termination protocols, alone at supported gestational stages or combined with a prostaglandin such as cloprostenol.
- Reported adjunctive control of persistent egg laying in selected psittacine birds.
- Reported preoperative mammary-tumor management and treatment of selected pituitary-dependent hyperadrenocorticism cases; evidence for these applications is limited.
Contraindications
- Pregnancy unless termination is intended.
- Discontinue before anesthesia because of hypotension risk.
- Ergot-derivative hypersensitivity; severe hepatic dysfunction requires caution.
Interactions
- Dopamine antagonists such as metoclopramide and phenothiazines reduce response.
- Other dopamine agonists or hypotensive drugs can increase effects.
Adverse effects
- Vomiting, especially above 5 mcg/kg
- Anorexia and lethargy
- Hypotension
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Galastop oral liquid 50 mcg/mL Do not refrigerate; discard 28 days after opening. | Oral Liquid | 50 mcg / mL | PO |
| Cabergoline 0.5 mg tablet | Tablet | 0.5 mg / tablet | PO |
| CB-Lin 0.5 mg tablet Serum Institute of India Pvt. Ltd. Single-active cabergoline tablet; strength is not a canine dose. | Tablet | 0.5 mg / tablet | PO |
| CB-Lin 0.25 mg tablet Serum Institute of India Pvt. Ltd. Single-active cabergoline oral tablet. | Tablet | 0.25 mg / tablet | PO |
Monitoring and Administration
May be given directly or with food. Treat pseudopregnancy initially for 4–6 days and repeat if signs persist.
Monitor response and cardiovascular tolerance; plasma cortisol monitoring is described during prolonged treatment.
Avoid skin and eye contact. People who may become pregnant should wear gloves; wash splashes promptly.
Keep the oral liquid at room temperature, protected from light; do not refrigerate and discard 28 days after opening.
When inducing estrus, wait at least four months after the previous cycle. For the low-dose 0.6 mcg/kg regimen, stop at day 2 after proestrus begins or after 42 days without proestrus.
A freshly made 10 mcg/mL aqueous solution from a 0.5 mg tablet in a final 50 mL is for use within 15 minutes; discard the remainder. This does not establish long-term aqueous stability.
Refractory pseudopregnancy protocols have combined cabergoline with metergoline 500 mcg/kg orally twice daily or bromocriptine 10–30 mcg/kg orally twice daily; do not substitute these combinations for uncomplicated single-agent treatment.