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Objective: Hyperprolactinemia is an important adverse effect of antipsychotic treatment. Hyperprolactinemia can lead to gynecomastia, galactorrhea, sexual dysfunction, infertility, oligomenorrhea, amenorrhea and osteoporosis. All of the typical antipsychotics are known to cause elevation in serum prolactin level. Atypical antipsychotics have a lower tendency for increasing serum prolactin levels when compared with typical antipsychotics, but effects of all atypical antipsychotics on serum prolactin levels are not similar. Paliperidone is a newly commercialized antipsychotic whose formulation includes the principal active metabolite risperidone and 9-hydroxyrisperidone, and it is claimed that it is an advantageous agent compared to risperidone, especially considering the side effects. We aim to research effects of atypical antipsychotics risperidone and paliperidone on serum prolactin levels and compare the results.
Methods: In this study, the records of inpatients treated with risperidone and paliperidone were screened retrospectively for the period from April 2014 to January 2015. The patients whose records had enough sociodemographic data and who had been screened for prolactin levels before treatment and in the second week of the treatment were included in the study. Patients who had already been in treatment were excluded; thus only new onset of risperidone or paliperidone is evaluated.
Results: A total of 95 patients were included in the study with diagnoses of schizophrenia, bipolar disorder, and other psychotic disorders. 83 patients have been treated with risperidone (risperidone group) and 12 patients with paliperidone (paliperidone group). The mean age of patients was 38.2 years and 48 were male, 47 were female. 53 patients were diagnosed with schizophrenia, 32 patients were with bipolar disorder, and 10 patients carried some other psychotic disorder. There were no significant differences between the risperidone group and the paliperidone group in the terms of age, gender and profile of psychiatric diagnosis. The mean initial serum prolactin level in patients was 47.5 ng/dl and the mean level measured in the second week of the treatment was 115.07 ng/dl. There was a significant increase of serum prolactin level after two weeks (p0.05).
Conclusion: This study suggests that paliperidone has no advantage over risperidone in serum prolactin levels. The results of the study also remind that patients who are under treatment with antipsychotics should be monitored regularly in terms of hyperprolactinemia and its associated symptoms. Further studies with larger sample size and over a longer time period are needed to highlight the effects of antipsychotics on serum prolactin levels.