Endocrine Abstracts

Introduction: Dopamine agonists (DAs) consisting of cabergoline (CAB) or bromocriptine is the primary therapy in prolactinomas. DAs are also used in Parkinson’s disease and restless leg syndrome with much higher doses. As a result of reports related to doses in these patients, it is known that long term use of DAs can lead to fibrotic syndromes affecting heart and lung. Cardiac valvulopathies are the most common investigated side effects but there are case reports of pleuropulmonary fibrosis. These reports raise concern for the safety of DAs in prolactinoma due to possible pulmonary side effects. Terefore we evaluated the pulmonary functions of prolactinoma patients receiving CAB treatment.

Patients and Methods: Seventy three patients who received CAB for at least 18 months are included in the study. Chest X-ray and pulmonary functions like forced vital capacity (FVC), total lung capacity (TLC) measurements and diffusion capacity monitoring with carbon monoxide (DLCO; normal range: 80-100%) were performed at the last visit of each patient. Patients with a history of pulmonary disease and using drugs which may deteriorate pulmonary function are excluded from the study. Data of the patients are reviewed retrospectively. Cumulative dose of CAB and the total time of CAB usage are calculated. All patients were evaluated by a pulmonologist and those with abnormal results were requested additional tests like high resolution computerized tomography (HRCT) of the chest if needed.

Results: The study consisted of 34 male and 39 female with a mean age of 43 years (range 22–78). The mean cumulative CAB dose was 244 mg (range 24–1298) and the mean time of CAB use was 75 months (range 18–300). Mean values of FVC, TLC and DLCO were 104 ± 14%, 102 ± 12%, 95 ± 16% respectively. Among 13 asymptomatic patients (17%) with abnormal DLCO results; 2 patients had significantly decreased DLCO (mean CAB cumulative doses; 120 and 175 mg) but physical examination and chest HRCT revealed no pathology, and the others had DLCO values just below the border but also with normal physical examination and chest X-ray findings. However, these abnormal DLCO results were not related to cumulative CAB dose in these patients (P = 0.6).

Conclusion: CAB appears to be safe for pulmonary function with mean cumulative doses of 244 mg in prolactinoma patients. But as low DLCO could be the early finding of interstitial lung disease, evaluation of pulmonary functions and follow-up according to the results may be rational during long term treatment of prolactinoma with DAs.