Dopamine agonists and weight changes in prolactinoma patients

Prolactinomas, the predominant pituitary adenoma type, are primarily treated with dopamine agonists to decrease prolactin levels and tumor size. The use of dopamine agonists has been shown to improve metabolic parameters and lead to weight loss in prolactinoma patients. However, the data is conflicting and sparse. In the current study, we aim to review weight variations in prolactinoma patients treated with dopamine agonists.

We identified prolactinoma patients referred to one pituitary clinic between 2010 and 2020. Data from prolactinoma patients treated with dopamine agonist therapy were retrospectively collected over the span of 1 year. Serum prolactin and weight measurements were obtained at the time of diagnosis and at 3-months, 6-months, and 12-month time points. We also collected information on the patient's age, sex, BMI, diabetes history, and dopamine agonist treatment regimen.

91 patients with prolactinoma treated with dopamine agonist were included in the study. Among the 91 patients, 47 were females and 44 were males. The average age for females was 30.5 years and for males were 49 years. The average BMI in females was 31.02 kg/m² and in men were 31.05 kg/m². The prolactin level at baseline was higher in men with an average of 779.95 ng/ml while in females' initial prolactin levels were 433 ng/ml. Prolactin levels decreased to normal levels as dopamine agonist treatment was continued over the course of one year, with the most precipitous drop occurring between 0 and 3 months. While prolactin levels at baseline were higher in men, prolactin levels in men dropped on average 644 ng/mL over the 0-3-month period, compared to the 257 ng/mL average drop in women. While not significant, patients overall lost weight over the treatment period, with men losing on average 7.8 pounds and women losing 1.1 pound.

The use of dopamine agonists for a duration of about 12 months did not result in statistically significant weight loss among patients with prolactinoma.