Optimal testosterone level to improve symptoms of hypogonadism without causing dopa-testotoxicosis in male macroprolactinoma.

Background: Male prolactinoma treatment by dopamine agonists (DA) restores sexual function. However, excessive DA dose can lead to impulse control disorder.

Objectives: The aim of this retrospective study was to determine the level of testosterone that eliminates symptoms and provides fertility in male macroprolactinoma, without causing these adverse effects.

Materials And Methods: Twenty-seven male patients with macroprolactinoma were included. There were 16 macro (≥1-2.8cm), 7 large macro (≥2.9-3.9cm) and 4 giant (≥4cm) adenomas. Prolactin (PRL) and testosterone (T) levels were evaluated. A timeline was created to analyze improvement in symptoms of hypogonadism and infertility. Testosterone levels were compared with age-matched controls.

Results: Mean PRL, basal tumor diameter and shrinkage were 2846±3415ng/mL, 27.2±10.2mm and 63.4%, respectively. Basal T levels were 1.6±1.0ng/mL for patients and 4.4±1.5ng/mL for controls (P<0.001). Mean T level in the asymptomatic period was significantly lower than in controls (3.2±0.4ng/mL vs. 4.4±1.5ng/mL, respectively; P=0.002), while mean PRL was 27.2ng/mL. Fertility was achieved in 6 of the patients seeking fertility, and there was no difference in T level between these patients and controls (3.7±0.8ng/mL and 4.4±1.5ng/mL, respectively; P=0.14); when fertility was achieved, mean PRL was 26.9±23ng/mL.

Conclusion: Patients should be carefully questioned regarding complaints at each consultation, and DA dose should not be increased unnecessarily, to avoid possible serious adverse effects.