Hyperprolactinemia induced by low-dosage amisulpride in Korean psychiatric patients

Aim: Amisulpride at low dosages enhances dopaminergic neurotransmission by preferentially blocking presynaptic D2/D3 receptors. Thus, low dosages of amisulpride are expected not to increase prolactin levels. The aim of this study was to examine whether low dosages of amisulpride can increase serum levels of prolactin or not clinically in Korean patients. Method: Serum prolactin levels were measured in 20 Korean patients (12 men and eight women) with various diagnoses who were treated with less than 300 mg of amisulpride per day. Results: The mean dosage of amisulpride was 195.0 ± 51.0 mg/day, and serum level of prolactin was 76.1 ± 43.4 ng/mL. The prolactin level was significantly higher in women (110.7 ± 49.3 ng/mL) than in men (53.1 ± 15.9 ng/mL) after administering amisulpride (P = 0.021), while the dosage of amisulpride did not differ significantly between men (200.0 ± 42.6 mg/day) and women (187.5 ± 64.1 mg/day) (P = 0.576). Conclusions: The low dosages of amisulpride elevate serum prolactin level in the majority of patients. This finding indicates that the dose-reduction of amisulpride has little effect to relieve amisulpride-induced hyperprolactinemia at therapeutic dosages. Clinicians should monitor serum prolactin level even when low dosages of amisulpride are administered.