Cabergoline

Key facts

• Cabergoline mimics dopamine, the brain chemical that normally suppresses the pituitary hormone prolactin. Lowering prolactin restores periods and fertility and stops unwanted milk production.
• It is taken by mouth once or twice a week, usually starting at a low dose that is increased gradually based on prolactin blood levels.
• Long-term cabergoline, especially at the higher doses used for Parkinson's disease, is linked to fibrosis (thickening and stiffening) of heart valves, which can cause valve leakage. Your prescriber assesses your heart before starting and periodically during long-term treatment.
• Seek urgent care for new breathlessness, ankle swelling, or a heart murmur noticed on examination.

What cabergoline treats

Cabergoline treats hyperprolactinaemia, abnormally high prolactin from any cause, including prolactin-secreting pituitary tumours (prolactinomas), where it usually shrinks the tumour as well as lowering the hormone level. It is also used, generally at higher doses, as an add-on treatment for Parkinson's disease. It is not a treatment for infertility unrelated to high prolactin, and it is not routinely used to suppress normal breast milk production after childbirth because of the valve-safety concern.

How cabergoline works

Cabergoline binds dopamine D2 receptors in the pituitary gland, the same receptors dopamine itself uses to switch off prolactin release. This lowers circulating prolactin, relieving absent periods, infertility and unwanted milk production, and often shrinks a prolactin-secreting tumour over months. In the brain's movement-control circuits, the same receptor action eases the tremor and stiffness of Parkinson's disease.

Before you take it

• Do not take cabergoline if you have a history of heart valve disease, fibrosis of the heart lining, lungs or abdomen, or uncontrolled high blood pressure.
• Tell your prescriber before starting if you have psychiatric illness: dopamine agonists can occasionally cause impulse-control problems such as compulsive gambling or shopping.
• Alcohol can worsen dizziness and low blood pressure with cabergoline.
• Other dopamine-blocking medicines, such as some antipsychotics and metoclopramide, can cancel out its effect and should be flagged to your prescriber.

Side effects

Common effects include nausea, headache, dizziness on standing, and fatigue, which usually ease as your body adjusts.

Stop and seek urgent medical care for any of these:

• Breathlessness, ankle swelling or chest pain.
• Fainting or severe dizziness.
• New compulsive behaviour, such as uncontrollable gambling, shopping or hypersexuality.

Safety essentials

• Heart valve fibrosis is cabergoline's defining long-term risk, particularly at higher, Parkinson's-disease doses. An echocardiogram (heart ultrasound) is recommended before long-term treatment and periodically afterward.
• Report new breathlessness or ankle swelling immediately; these can signal valve or fibrotic changes needing investigation.
• Have prolactin levels checked regularly so your dose can be kept as low as effective.
• Buy cabergoline only from a licensed pharmacy.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.