Endocrine Abstracts

Case 1: A 33-year-old male patient with seven years of erectile dysfunction and aspermia presented for a fertility opinion. He had a diagnostic of macroprolactinoma a year ago when Cabergoline was started with a gradual increase of the dose. Upon his initial evaluation in our clinic, on 2 mg Cabergoline weekly, his serum PRL level was × 10 UNL, decreased 70% from the diagnostic, and the tumour shrinkage was 60% from the diagnostic. A gradual increase of the Cabergoline up to 4.5 mg weekly and hypogonadism treatment with recombinant LH was planned. After the couple succeeded in conceiving, the patient was converted to testosterone substitution therapy. A year after increasing the dose to 4 mg Cabergoline weekly, the adenoma shrunk by 30% in volume, and the prolactin level maintained fivefold UNL. Case 2: A 44-year-old female patient with a diagnostic of macroprolactinoma abutting the optic chiasm – with constant treatment on Cabergoline 2 mg weekly in the last 18 months was referred to evaluation for a 2 mm progression of the adenoma. She had normalisation of the prolactin and regular menstrual cycles. The visual field examination reveals a slight abnormality in the temporo-superior quadrant. A gradual increase to 4 mg of Cabergoline weekly was planned with good tolerance. The six-month follow-up in the visual field examination showed a slight improvement. In case adverse effects do not develop, a high dose of Cabergoline remains a therapeutic option. Patients must be informed of the potential long-term side effects of high doses of Cabergoline, mainly the risk of cardiac valvular or pleural fibrosis. Some studies have shown little benefit to further increasing the cabergoline dose beyond 4 mg per week, considered the maximally effective dose while waiting for time effects, leading to hormonal control after several months in a substantial proportion of initially resistant patients. The use of Anastrozole, an aromatase inhibitor, to counter the further increase in drug resistance induced by testosterone supplementation, noted in a few cases, allowing a significant reduction of prolactin concentrations with lower doses of Cabergoline.