Clinical use of cabergoline as primary and adjunctive treatment for acromegaly

Cabergoline is a dopamine agonist that may be used as primary or adjunctive therapy for acromegaly. Although one study suggested biochemical control may be achieved in a substantial proportion of patients, it is still commonly perceived to be a relatively ineffective treatment.

A prospective audit was performed of 15 consecutive acromegalic patients (eight males, seven females, median age 55, range 31-92 at presentation) treated with cabergoline to determine the effective dose and tolerability. All had normal anterior pituitary function; two patients had hyperprolactinaemia. Magnetic resonance imaging revealed nine adenomata, two partially empty sellae and four structurally normal pituitary glands. Nine patients had undergone transsphenoidal surgery 1-12 months, and one patient had received pituitary radiotherapy 18 years, prior to commencement of cabergoline. All patients had biochemical GH excess; median serum IGF1 471 ng/ml, range 239-746 ng/ml. The calculated mean of a series of GH measurements ranged from 2.7-45.8 mIU/l, median 9.7 mIU/l.

On a median weekly dose of cabergoline of 1.75 mg (range 0.5-7 mg) normalisation of both IGF1 and GH occurred in 4 out of the 15 patients (27%). Out of the 15 patients (33%), 5 achieved a serum IGF1 within the reference range with notable reductions seen in a further five patients. Nine patients (60%) achieved a mean serum GH level of less than 5 mIU/l. Duration of treatment was 2-52 months and was well tolerated in 14 patients.

Cabergoline can be an effective and well tolerated primary or adjunctive therapy for acromegaly and useful clinical responses are noted even with modest doses.