Patients with schizophrenia found Pfizer's atypical antipsychotic, Geodon (ziprasidone) to be more tolerable than-and just as effective as-Risperdal (risperidone), according to a head-to-head study published in a recent issue of the Journal of Clinical Psychiatry.

Results from the eight-week study showed that Geodon and Risperdal were equally effective in improving psychotic symptoms associated with schizophrenia and schizoaffective disorder. However, Geodon showed a lower movement disorder burden, which can include stiffness, rigidity, tremors and restlessness; reduced effects on weight; and a more favourable impact on prolactin levels, which can be associated with sexual dysfunction and menstrual irregularity. In fact, Risperdal-treated patients had prolactin levels that were three times greater, on average, than those patients treated with Geodon, an official statement from Pfizer said.

"Poor tolerability is one of the most common barriers to patient compliance. If a medicine's side effects are distressing enough, patients may stop taking it even if it is working to manage their disorder and for people with schizophrenia, this could lead to significant worsening of psychosis," said Dr. Peter Buckley, professor and chairman of the Department of Psychiatry and Behavioural Health at the Medical College of Georgia. "This study shows that Geodon demonstrates efficacy on par with what is considered a well established treatment for efficacy and well-tolerated with reduced risks for certain harmful side effects that commonly affect patients with schizophrenia," Dr Buckley added.

During the course of the trial, twice as many patients treated with Risperdal experienced clinically significant weight gain, at least 7 percent or more of baseline weight, as those treated with Geodon.

Patients treated with Geodon were also less likely to demonstrate akathisia (restlessness) and experienced a lower movement disorder burden (MDB). The MDB score was 0.35 at end point for the Risperdal group compared to 0.20 for the Geodon group with the higher score indicating greater adverse effect burden.

Approved in the United States in February of 2001 for the treatment of schizophrenia and in 2004 for acute bipolar mania, Geodon is licensed in 73 countries, and more than 4.5 million prescriptions have been written worldwide. It is widely accepted on hospital, Medicaid, national VA and managed care formularies.

Discovered and developed by Pfizer, Geodon is a serotonin and dopamine antagonist.