De Novo delayed onset hypothermia secondary to therapeutic doses of risperidone in bipolar affective disorder.

The commonly reported side effects related to risperidone include dizziness, nausea, weight gain, sleep disturbances, and sexual dysfunction. A rather rare and very much less documented side effect of risperidone is hypothermia: traditionally defined as a drop in core body temperature below 35°C (95°F). We report a case of a 75-year-old woman who had been treated for bipolar affective disorder for nearly 3 years with risperidone went on to develop hypothermia which was reversed with the withdrawal of the offending drug. This case is unique as it reported a rare but potentially serious side effect occurring after a prolonged administration of risperidone contrary to the previous reports in which hypothermia occurred only a few hours or days after the administration of risperidone and occurred in a patient who was diagnosed as having bipolar affective disorder as opposed to schizophrenia, the most common psychiatric disorder associated with previously reported hypothermia. The authors would like to emphasize the importance of this idiosyncratic potentially life-threatening adverse effect of risperidone-induced hypothermia to all clinicians, which occurs regardless of the duration of drug intake, in order to help them identify the condition early and treat it effectively.