Short-term management of macroprolactinomas with a new injectable form of bromocriptine

Three cases (2 men, 1 woman) of expansive macroprolactinoma treated with a single 50-mg intramuscular dose of a new form of injectable, long-acting bromocriptine are presented. Clinical manifestations included visual disturbances (2 cases), headache (1 case), and hypogonadism (3 cases). Laboratory tests demonstrated high basal serum prolactin (PRL) levels and evidence of involvement of other anterior pituitary hormones in all cases. Treatment was followed by marked improvement of symptoms paralleled by a sharp decrease of serum PRL levels, which normalized in 1 case. Some other anterior pituitary functions also improved. Computed tomography scan revealed shrinkage of the tumor in all cases. There were no local or serious systemic side effects. These initial findings suggest that long-acting injectable bromocriptine has a place in the initial treatment of macroprolactinomas, especially for those with neurological and/or visual manifestations. It can also be used to select patients for surgery, in the cases where clinical and radiological improvement could not be obtained. The effects of long-term use remain to be established by further studies.