Olanzapine and aripiprazole is effective, safe, and well tolerated for the positive and negative symptoms in schizophrenia. Hyperprolactinaemia is a frequent side-effect in the use of atypical antipsychotics. The endocrine and sexual side effects related to hyperprolactinaemia significantly impair in breast cancer patients.

The effect combination of a low doses olanzapine and aripiprazole were examined in a sample of 21 breast cancer patients who had the schizophrenia and olanzapine-induced hyperprolactinaemia. They were randomly assigned to experimental or control groups. They were interviewed by psychiatrists and tested using Positive and Negative Syndrome Scale (PANSS) at baseline and follow-up visits. Plasma prolactin level was assessed at baseline and at the end of the study. The patients of control group received olanzapine as their sole antipsychotic agent at a maximum dose of 5 mg once daily. The patients’ experimental group received olanzapine at a maximum dose of 5 mg once daily in combination with aripiprazole at a maximum dose of 10 mg once daily.

No differences between initial groups were identified. The results of our study suggest that after three weeks of schizophrenia treatment, 81,8% patients from the experimental group and 40% from the control group showed significant clinical improvement. At the end of weeks 3, serum prolactin levels were normalized (7.9+/-4.7 micrograms/L) in patients’ experimental group.

These data show that combination of a low doses olanzapine and aripiprazole for treatment schizophrenia in breast cancer patients may result in enhanced antipsychotic efficacy while reducing adverse effects including olanzapine-induced hyperprolactinaemia.