Cabergoline Improves Metabolic Status in Hyperprolactinemia

Researchers published the study covered in this summary on as a preprint that has not yet been peer reviewed.

Key Takeaways

  • Patients with hyperprolactinemia secondary to a newly diagnosed prolactinoma who received 6 months of treatment with the dopamine agonist cabergoline showed significant improvements in several cardiovascular risk factors including triglyceride-glucose index, a surrogate marker of insulin resistance.

Why This Matters

  • Prolactinoma is one of the most prevalent pituitary adenomas, affecting about 40% of all patients with a pituitary adenoma.

  • Evidence suggests that high levels of prolactin (PRL) ared associated with an increased risk for cardiovascular morbidity and mortality might be mediated by exacerbation of cardiovascular disease risk factors such as dyslipidemia, insulin resistance, obesity, and glucose intolerance.

Study Design

  • The study involved 71 patients from a single endocrinology clinic in Gorgan, Iran with newly diagnosed prolactinoma who had symptoms and signs of hyperprolactinemia for more than 6 months, serum PRL levels that were at least twofold above the normal range, and an MRI that identified a pituitary adenoma.

  • The study excluded people with hypothyroidism, a history of malignancy, or known diabetes, those taking agents that could increase PRL levels or lipid-lowering medications, and pregnant women.

  • Participants received 0.25 mg cabergoline twice weekly. They reached this target level after gradual dose increases that were guided by each patient’s PRL level. Patients received cabergoline for 6 months.

  • Patients underwent clinical and laboratory assessments at baseline and after 3 and 6 months on treatment, including measures of PRL levels, fasting plasma glucose, various lipids, and uric acid performed in the morning after a 12-hour fast.

Key Results

  • The average age of participants was 36 years old, and 41 (58%) were women.

  • Participants showed significant declines in average body mass index (BMI), waist circumference, and PRL levels from baseline to 6 months.

  • They also had a small but significant decline in average fasting plasma glucose at 3 and 6 months compared with their baseline levels.

  • Participants showed significant and more substantial improvements in several lipid levels that often continued to improve with ongoing treatment. Average triglyceride levels in the women fell from an average 182 mg/dL at baseline to 148 mg/dL after 3 months and to 121 mg/dL after 6 months. In men, average level decline from 196 mg/dL at baseline to 168 mg/dL and 165 mg/dL after 3 and 6 months.

  • Average low-density lipoprotein cholesterol levels also dropped in women from 162 mg/dL at baseline to 110 mg/dL after 3 months and to 117 mg/dL after 6 months. Among men, the average level fell from 168 mg/dL at baseline to 126 mg/dL after 3 months and to 143 mg/dL after 6 months.

  • Average levels of high-density lipoprotein cholesterol increased in women from 37 mg/dL at baseline to 44 mg/dL after 3 months and to 45 mg/dL after 6 months. Men again had similar changes, with the average level rising from 36 mg/dL at baseline to about 43 mg/dL after both 3 and 6 months on treatment.

  • Uric acid levels were significantly reduced only among women.

  • Both women and men showed significant reductions in average triglyceride-glucose index. In women, it fell from 8.99 at baseline to 8.76 after 3 months and to 8.57 after 6 months. In men, the average dropped from 9.13 at baseline to 8.94 after 3 months and to 8.87 after 6 months.

  • Men had a significant decline in the prevalence of metabolic syndrome, from 77% at baseline to 43% after 3 months and 60% after 6 months, but this was not the case among women, who had a fairly flat trajectory during follow-up.


  • The observational basis of the study precludes making conclusions about causality.

  • The duration of patient follow-up was relatively brief.


  • The study received no commercial funding.

  • None of the authors had disclosures.

This is a summary of a preprint research study, “Metabolic effects of dopamine agonists treatment among patients with prolactinomas,” written by researchers at several centers in Iran, on Research Square, provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on

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