Antipsychotic-Related Prolactin Changes: A Systematic Review and Dose-Response Meta-analysis

Prolactin increase is a common and potentially problematic adverse event of antipsychotics. We aimed to discover the relationship between antipsychotic doses and changes in prolactin levels.

To examine the relationship between antipsychotic doses and changes in prolactin levels in adults with acutely exacerbated schizophrenia.

We searched the Cochrane Schizophrenia Group register (last search 26 July 2024) and previous reviews for fixed-dose, randomized controlled trials (RCTs) that investigated monotherapy of 21 antipsychotics in adults with acutely exacerbated schizophrenia. The primary outcome was mean prolactin change from baseline to study endpoint adopting mean differences (MD) in ng/mL as the effect size measure. The dose-response curves were estimated by conducting random-effects dose-response meta-analyses using the restricted cubic spline method.

Among 165 eligible studies, 68 studies with 238 dose arms (23,128 participants, 35% female) reported on prolactin and were meta-analyzed. Of these, 94% lasted ≤ 3 months, and 90% of the studies used oral formulations. Participants in one study experienced their first episode, while all other studies also included multiepisode participants. The dose-response curves indicated that with aripiprazole, higher doses were significantly associated with lower prolactin levels than lower doses. Brexpiprazole, cariprazine, lumateperone, and quetiapine carried negligible risks for prolactin increase across examined doses. During treatment with most other antipsychotics, i.e., asenapine, haloperidol, iloperidone, lurasidone, olanzapine, paliperidone, risperidone, and ziprasidone, prolactin levels rose with increasing doses and then continued to increase or plateaued. The shape of the dose-response curves was similar in males and females, with generally larger amplitudes of the curves in females.

The prolactin-increasing property varies among antipsychotics, is dose-related, and is greater in females. These findings in adults with acutely exacerbated schizophrenia can help clinicians titrate and adapt antipsychotic doses and consider patients' sex in treatment decisions. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO); registration no. CRD42020181467.