Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Dostinex (Pharmacia)
0.5 mg tablets
Indication: hyperprolactinaemia

Cabergoline is a synthetic ergoline derivative which stimulates D2 dopamine receptors. This stimulation reduces prolactin secretion.

The effect of cabergoline begins within 3 hours of taking the drug and may last for up to 28 days after a single dose. The elimination half life is estimated to be between 80 and 115 hours in hyperprolactinaemic patients. Most of the drug is metabolised and elimination is mainly in the faeces.

Cabergoline should be started at a low dose and increased at monthly intervals. The drug can be given once or twice a week in hyperprolactinaemia.

If the drug is used to prevent lactation, a single 1 mg dose is recommended on the first day after delivery. The drug is not approved for the inhibition of established lactation and should only be used to prevent lactation when there are medical reasons e.g. after a stillbirth.

Cabergoline has been compared with bromocriptine in double blind studies. For the prevention of lactation, one day's treatment with cabergoline was as effective as two weeks' treatment with bromocriptine. Cabergoline was better tolerated.1 In women with hyperprolactinaemic amenorrhoea, pregnancy or ovulatory cycles are more likely to occur during cabergoline treatment. Significantly more women achieve normoprolactinaemia with cabergoline.2

The adverse effects of cabergoline include nausea, headache, dizziness and reduced blood pressure. Adverse effects were reported by 16% of women in the study of inhibition of lactation and 68% in the study of hyperprolactinaemia. The corresponding figures for bromocriptine were 27% and 78%.

If post marketing surveillance confirms the advantages of cabergoline, it may eventually supersede bromocriptine.