Hyperprolactinemia in response to antipsychotic drugs: Characterization across comparative clinical trials

Background: Atypical antipsychotic drugs for the treatment of schizophrenia provide effective treatment of psychotic symptoms with a safety profile superior to conventional antipsychotic medications. Neuroendocrine abnormalities in patients with schizophrenia, such as chronic hyperprolactinemia, may now potentially be minimized by the use of newer prolactin-sparing antipsychotic drugs. A discrimination of prolactin-sparing versus prolactin-elevating antipsychotic drugs may provide the clinician with treatment choices in order to avoid or mitigate hyperprolactinemia-associated morbidity. Methods: Results from five clinical trials were used to characterize factors that may influence antipsychotic drug effects on levels of serum prolactin. Factors investigated included drug treatment, gender, time course, potential for reduction or reversibility, and age. Results: Factors that influenced the risk of hyperprolactinemia included gender, with females appearing to be more sensitive than males, and drug treatment, with risperidone and conventional antipsychotic agents increasing prolactin more than olanzapine. Patients of all ages demonstrated sensitivity to increased prolactin. Furthermore, patients with hyperprolactinemia sustained the effect over time. Hyperprolactinemia reversed when patients were switched to a prolactin-sparing antipsychotic medication. Conclusion: Effects of antipsychotic medications on serum prolactin are multi-factorial. Evidence for sexual, reproductive, and general medical consequences of antipsychotic-induced hyperprolactinemia is developing, and identifying antipsychotic drugs with a favorable prolactin profile would be important in mitigating these consequences. Most notably for women, atypical or novel antipsychotic drugs with a prolactin-sparing profile may offer effective clinical treatment with preservation of physiological hormonal function.