Background: Aripiprazole as a partial dopaminergic agonist reduces prolactin level in most users. We present a clinical study to follow up serum prolactin level in patients treated with aripiprazole. Methods: This is randomized open-label trial on serum prolactin monitoring in schizophrenic subjects. We enrolled 48 inpatients (29 Males, 19 Females) meeting DSM-IV criteria for schizophrenia from one Taiwan psychiatric hospital. After consent form fulfilled, participants were randomly assigned to three different treatment arms (dosage per day): (1) A - 10~15 mg aripiprazole ; (2) B - 20~30mg aripiprazole; (3) C - 10 mg aripiprazole combined with 1 mg risperidone. All subjects were evaluated by using PANSS scale and serum prolactin level at baseline, 4th week, 8th week, and 12th week. Other demographic data were also collected.Results: The mean prolactin level reduced from 54.1± 40.9 (baseline) to 12.0± 24.8 (12th week) with a p-value < 0.00001. The comparison of prolactin level between three arms of aripiprazole intervention shows no significant difference, although the reduction trend of Arm C was more than the other two Arms. The maximal prolactin level reduction was observed in the third week of aripiprazole, after adjusted for sex and previously prescribed antipsychotics.Conclusions: It is suggested that prolactin level returns to normal after 3 weeks of aripiprazole treatment progressively and remains until the 12th week. The prolactin level is not observed elevated by 1mg risperidone in Arm C. This may be explained by the high affinity to dopaminergic receptors in aripiprazole.
