Cabergoline: lowering prolactin, monitoring and cautions

Cabergoline is an ergot-derived dopamine agonist. The emc entry for Dostinex describes it as a potent, long-lasting prolactin-lowering medicine that stimulates D2 receptors on prolactin-producing cells of the pituitary. It is licensed for disorders linked to excess prolactin, including absent periods, infertility and prolactin-secreting pituitary tumours, and for stopping or suppressing milk production after delivery in specific situations.

High prolactin can have many causes. Your endocrinologist will look for those, including medicines, an underactive thyroid or a pituitary tumour, before deciding on treatment. A dedicated NHS patient page was not available when checked.

For high prolactin the SmPC describes starting with a small weekly dose and increasing gradually, typically at monthly steps guided by prolactin blood tests, to a usual weekly maintenance amount within a stated range. Taking tablets once or twice a week can be easy to mix up, so link it to specific days. Different regimens apply for stopping lactation, so these are not self-directed.

Long-term high-dose use of ergot-derived dopamine agonists has been linked to fibrosis of heart valves, lungs, pleura and the retroperitoneum. The SmPC says valve disease and related effects such as pericarditis and effusion occur very commonly during long-term use and asks for an echocardiogram at baseline and every six to twelve months, with chest imaging and lung function where relevant. Prolactin levels are measured monthly during dose changes. New breathlessness, persistent cough, chest pain, ankle swelling or back or abdominal pain should be reported.

• Report breathlessness, persistent cough, chest pain or swelling.

• Keep appointments for scans and prolactin tests.

Cabergoline can cause postural hypotension, so stand slowly. Sudden sleep-onset episodes have occurred, and impulse-control disorders including pathological gambling, increased libido, hypersexuality and compulsive spending or eating are described; families sometimes notice these first. Depression and psychotic symptoms are possible. Tell your prescriber if you notice any of these changes, because dose reduction or stopping can resolve them.

The SmPC lists headache, dizziness, nausea, tiredness, lower blood pressure and depression among frequent effects, besides the valve findings noted above. Taking tablets with food may help nausea.

Contraindications include a history of fibrotic disorders, evidence of cardiac valvulopathy, severe liver insufficiency, sensitivity to ergot alkaloids, and, for lactation use, a history of puerperal psychosis. Dopamine antagonists such as antipsychotics and metoclopramide reduce its effect. Macrolide antibiotics can raise cabergoline levels, and antihypertensives may add to blood pressure lowering.

The SmPC says to stop on confirmation of pregnancy because pituitary tumours can enlarge, and to discontinue about a month before planned conception, so discuss fertility plans with your endocrinologist before trying. Cabergoline suppresses lactation, so it is not used by mothers who wish to breastfeed. Drowsiness and sudden sleep episodes mean extra care when driving or operating machinery.

Mark your weekly tablet day on a calendar or phone, keep a list of scan and blood test dates, and tell every new prescriber that you take cabergoline, since antipsychotics, metoclopramide and macrolide antibiotics are among the medicines that interact.

It is prescription only. The emc lists Dostinex and Cabaser brands as well as generic tablets. Suspected side effects can be reported through the Yellow Card scheme.