Ziprasidone for Schizophrenia and Bipolar Disorder: A Review of the Clinical Trials

Ziprasidone is a newer “atypical” or “second-generation” antipsychotic. Oral ziprasidone (ziprasidone hydrochloride) is approved by the U.S. Food and Drug Administration (FDA) for the treatment of schizophrenia, and acute manic or mixed episodes associated with bipolar disorder (with or without psychotic features). Ziprasidone intramuscular (ziprasidone mesylate) is FDA-approved for acute agitation in patients with schizophrenia. Oral ziprasidone appears efficacious, and has been shown to have some limited clinical advantages over chlorpromazine and haloperidol in ameliorating negative symptoms of schizophrenia. In Phase 2 of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) for schizophrenia, ziprasidone did not match the clinical performance of olanzapine and risperidone, appearing closer in overall effectiveness to quetiapine. The rate of dose titration and the dose achieved may have an important bearing on ziprasidone's efficacy profile. In studies of usage for acute agitation in individuals with schizophrenia, intramuscular ziprasidone has been shown to be efficacious and relatively well tolerated. Regarding tolerability, ziprasidone, has important advantages in that it is not associated with clinically significant weight gain or adverse changes in cholesterol, triglycerides, or glycemic control, and patients may experience moderate improvement in these measures when switching to ziprasidone from a different antipsychotic agent. It also lacks significant persistent effects on prolactin levels, is not anticholinergic, and only infrequently causes extrapyramidal side effects or postural hypotension, although it can be associated with somnolence. This tolerability profile may be quite valuable in the treatment of some patients. Ziprasidone may prolong the electrocardiogram (ECG) QTc interval (QT interval corrected for heart rate by a standard algorithm), but after 5 years' clinical availability ziprasidone (by itself) does not appear to pose a substantial clinical problem in this regard. Therefore, ziprasidone may be considered a first-line drug option in the treatment of schizophrenia or manic episodes, but, in view of the differences among antipsychotic medications, drug selection should be guided by the patient's individual characteristics and situation.