n. an atypical antipsychotic that is used for the treatment of schizophrenia and of acute manic or mixed episodes associated with bipolar disorders. It may prolong the Q-T interval of the cardiac cycle (see electrocardiographic effect) and therefore should not be taken by patients with abnormal heart rhythms or by those who have had a recent heart attack or are taking antiarrhythmic drugs. Common side effects include orthostatic hypotension and sedation. U.S. trade name: Geodon.