Effects of aripiprazole, quetiapine and ziprasidone on plasma prolactin levels in individuals with first episode nonaffective psychosis: Analysis of a randomized open-label 1year study.

RATIONALE: Hyperprolactinemia is considered a troubling adverse effect of antipsychotics. Direct comparisons among second generation antipsychotics are scant in clinical practice. We hypothesize prolactin-sparing second-generation antipsychotics may have differential effects on prolactin levels and that they may be influenced by sex.

OBJECTIVES: To explore the differential effect of three widely used prolactin-sparing antipsychotics, aripiprazole, quetiapine and ziprasidone, on prolactin plasma levels in first episode non-affective psychosis during a 1year of treatment.

METHOD: From October 2005 to January 2011 a prospective, randomized, open-label study was undertaken. 141 patients who were randomly allocated to aripiprazole (N=56), quetiapine (N=36) or ziprasidone (N=49) were analyzed. The main outcome was differences in prolactin plasma levels over 1year follow-up among the three antipsychotics. Prolactin levels had a skewed distribution and therefore they were log-transformed before statistical analyses.

RESULTS: Male patients on aripiprazole had a lower risk of suffering an increase on prolactin plasma levels (N=71; F=12.645; p<0.001). There was a gender effect with smaller changes in mean prolactin values only in males. Aripiprazole had a reduced risk of hyperprolactinemia (aripiprazole 19.6%) compared to quetiapine (44.4%) and ziprasidone (32.7%) (p=0.038); and quite similar findings were found when investigating males (p=0.040). No significant differences were found in females. The percentages of mild prolactin excess were: 14.3% on aripiprazole, 36.1% on quetiapine and 18.4% on ziprasidone (χ2 =6.611 p=0.037).

CONCLUSIONS: Our findings provide additional evidence of differential effects of three sparing-prolactin antipsychotics on prolactin release and may help clinicians to decide among therapeutic options.