Cabergoline. A review of its pharmacological properties and therapeutic potential in the treatment of hyperprolactinaemia and inhibition of lactation.

Cabergoline is a synthetic ergoline which shows high specificity and affinity for the dopamine D2 receptor. It is a potent and very long-acting inhibitor of prolactin secretion. Prolactin-lowering effects occur rapidly and, after a single dose, were evident at the end of follow up (21 days) in puerperal women, and up to 14 days in patients with hyperprolactinaemia. In the only comparative study to date, cabergoline 0.5 to 1.0 mg twice weekly was more effective than bromocriptine 2.5 to 5.0 mg twice daily in the treatment of hyperprolactinaemic amenorrhoea, restoring ovulatory cycles in 72% of women and normalising plasma prolactin levels in 83%, compared with 52 and 58%, respectively, for bromocriptine. In the prevention of puerperal lactation, a single dose of cabergoline 1.0mg was as effective as bromocriptine 2.5mg twice daily for 14 days. A significantly lower incidence of rebound lactation in the third postpartum week was seen with cabergoline. Unpublished data suggest cabergoline 0.25mg twice daily for 2 days is effective in suppressing established puerperal lactation in about 85% of women. Nausea, vomiting, headache and dizziness are characteristic adverse events of the dopaminergic ergot derivatives. Cabergoline appears to be better tolerated than bromocriptine in both patients with hyperprolactinaemia and postpartum women. Most patients intolerant of other ergot derivatives can tolerate cabergoline. Bromocriptine use in the puerperium has been associated with an increased risk of serious thromboembolic events. However, there are no such reports with cabergoline and whether these events will become associated with other dopaminergic agents is unknown. The teratogenic potential of cabergoline has not been extensively investigated in humans. Ten congenital abnormalities have been reported in 199 cabergoline-associated pregnancies. Although there is no pattern to these abnormalities, the limited experience with cabergoline in pregnancy means the drug cannot be considered as a first-line therapy for the treatment of infertility associated with hyperprolactinaemia. At this stage of its development, cabergoline will prove useful in patients with hyperprolactinaemia who have failed treatment with, or are intolerant of, other dopamine agonists such as bromocriptine. If drug treatment is required for the prevention or suppression of puerperal lactation, cabergoline offers significant advantages over bromocriptine and should become the drug treatment of first choice for this indication.