Objective To find the optimal changes needed for resolution of amenorrhoea associated with risperidone. Method Between November 2001 and May 2002, 16 female outpatients who had taken risperidone for more than 3 months voluntarily reported amenorrhoea. Following each report of amenorrhoea, serum prolactin level was measured and treatment changes were undertaken. The menstrual cycles and clinical mental status of each patient were followed for the next 6 months. For nine of the 16 patients, the dose of risperidone was reduced. For the other seven patients, risperidone was switched to olanzapine or quetiapine. Results Fourteen of 16 patients had hyperprolactinemia. Two patients who had discontinuation of risperidone recovered from amenorrhoea and three of the risperidone-reduction patients resumed their periods. All subjects in the drug-switch patients recovered. The patients who recovered from amenorrhoea at a reduced dosage of risperidone took ≤3 mg/day. Two patients in the risperidone-reduction group dropped out. Conclusion Stopping risperidone (without starting any other antipsychotic) or switching to a prolactin-sparing antipsychotic is an effective strategy for resolution of amenorrhoea on risperidone, but that dose reduction is rarely effective either because amenorrhoea continues despite lower dose or because relapse of psychosis appears.
Keywords: Prolactin; amenorrhea; mood disorder; risperidone; schizophrenia.