DEPOT‐BROMOCRIPTINE TREATMENT FOR PROLACTINOMAS AND ACROMEGALY

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Abstract
Fifteen patients with hyperprolactinaemia and pituitary macroadenomas (5 patients), microadenomas (6 patients), or acromegaly (4 patients) were given a single intramuscular injection of 50 mg bromocriptine bound to polylactic acid microspheres, depot‐bromocriptine. None of the patients had any short‐term or long‐term discomfort from the injection. In the 11 patients with prolactinomas, serum prolactin fell to minimum levels 12–72 h post‐injection; nine patients were highly responsive to depot‐bromocriptine, with a mean serum prolactin of 12·9% of basal levels 24 h post‐injection, rising to 19% at 28 days. Two patients with prolactinomas were resistant to both depot‐bromocriptine, and large doses of oral dopamine agonists. Initiating side‐effects (nausea, vomiting, symptomatic postural hypotension) were seen in five patients in the first 24 h post‐injection, but were minimal or absent thereafter. Five of six patients previously intolerant of oral dopamine agonists were able to be transferred successfully to bromocriptine 5 mg daily at 4 weeks. Of the four patients with acromegaly, raised prolactin levels were successfully lowered to normal for 4 weeks after injection; serum GH was also partially lowered, but returned to baseline levels at 2–4 weeks. In one patient serum GH was resistant to suppression by both depot bromocriptine and high doses of oral bromocriptine. One patient with a large tumour and visual field defects showed a rapid and maintained improvement in visual fields and acuity after depot‐bromocriptine, and was successfully transferred to high‐dose oral bromocriptine at 4 weeks. In the total group of 15 patients, computed tomography (CT) scans showed clear tumour shrinkage in seven patients 4 weeks post‐injection. It is concluded that depot‐bromocriptine is a significant improvement in the initiation of treatment for hyperprolactinaemia and acromegaly. It allows the rapid diagnosis of bromocriptine resistance, and the initiation onto oral dopamine agonist therapy of some patients said to be intolerant of such therapy. Furthermore, it may well be the treatment of choice for rapid shrinkage of large pituitary tumours sensitive to dopamine agonist therapy.