Effect of Typical and Atypical Antipsychotics on Plasma Prolactin Levels in Schizophrenia

Background: Hyperprolactinaemia is a common side-effect of antipsychotic treatment and the clinical consequences associated with this can have a negative impact on patients compliance. The aim of this study was to compare the frequency of hyperprolactinemia in patients with schizophrenia treated with atypical antipsychotic olanzapine and typical antipsychotic haloperidol. Material & Methods: This was a cross-sectional, analytical study conducted at the Department of Psychiatry, AFIMH, Rawalpindi over a period of six months. It included 60 patients and 30 healthy controls. All patients underwent a thorough psychiatric evaluation for fulfilling the ICD-10 criteria of schizophrenia. They were then randomly allocated into two groups. Baseline fasting serum prolactin levels were taken followed by administeration of haloperidol and olanzapine respectively. A second serum prolactin level was then taken and assessed by the same prolactin measuring kit. With these two groups being given haloperidol and olanzapine alongside serum prolactin levels were similarly measured for healthy controls. Results: Elevated Prolactin levels were found in 25(89%) of the patients receiving haloperidol and 12(32%) of patients receiving olanzapine, but in none of the healthy controls. There was a significant difference in median prolactin level among both the treatment groups (p<0.001), in that the prolactin level was significantly higher in the patients treated with haloperidol and moderately high in the patients treated with olanzapine, compared to the healthy controls. Conclusion: The typical antipsychotic haloperidol significantly elevates the prolactin levels while atypical antipsychotic olanzapine only moderately raises the prolactin levels.