Improvement in hyperprolactinemia and reproductive comorbidities in patients with schizophrenia switched from conventional antipsychotics or risperidone to olanzapine

SummaryThis open-label, prospective, 4-month study in hyperprolactinemic patients with schizophrenia explored whether prolactin levels decrease after switching antipsychotic therapy to olanzapine. A secondary objective was to determine if reproductive morbidities and sexual dysfunction occurring with hyperprolactinemia improved with prolactin normalization. Clinically stable patients with schizophrenia, who had hyperprolactinemia defined as >18.8 ng/ml for males and >24.2 ng/ml for females, were randomized to: remain on current therapy (n=27) or switch to olanzapine, 5–20 mg/day, (n=27). Baseline prolactin levels in female patients randomized to receive olanzapine (n=14) were 66.3±38.7 ng/ml and were 82.0±37.6 (p=.32) in those remaining on their pre-study antipsychotic medication (n=14). In male patients, baseline prolactin levels were 33.7±12.1 and 33.5±13.8 ng/ml (p=.97), respectively, for those randomized to olanzapine (n=13) or remaining on pre-study treatment (n=13). At study end, patients switched to olanzapine experienced significant reductions in mean serum prolactin levels of 19.8±18.1 ng/ml in males (p=.02), and 32.3±47.5 ng/ml in females (p=.01), but prolactin continued to be elevated in patients who remained on pre-study antipsychotic treatment. After switching to olanzapine treatment, male patients experienced significantly (p=.03) increased free testosterone levels but there were no significant improvements in total testosterone levels; some female patients experienced improved menstrual cycling, as well as resolution of galactorrhea and gynecomastia, and sexual functioning was significantly improved in both genders. Patients switched to olanzapine, as well as those remaining on their pre-study medication, maintained clinical stability, their symptoms continued to improve, although there were no significant between-treatment differences in improvement. Treatment-emergent adverse events did occur in both treatment groups; however, they were not significantly different between groups. Olanzapine-treated patients experienced significantly lower eosinophil counts and higher elevations in low-density lipoproteins and standing blood pressure than non-switched patients. Olanzapine treatment may offer sustained reduction in serum prolactin and improvement in sexual and reproductive comorbid symptoms in patients with schizophrenia who have treatment-emergent hyperprolactinemia.