Clozapine Rarely Prescribed for Refractory Schizophrenia

Fran Lowry

June 16, 2011

June 16, 2011 (Boca Raton, Florida) — Clozapine, an effective antipsychotic medication for treatment-resistant schizophrenia, is not being prescribed as often as it should be, researchers reported here at the New Clinical Drug Evaluation Unit (NCDEU) 51st Annual Meeting, sponsored by the American Society of Clinical Psychopharmacology.

"Study after study shows clozapine, which is the first of the second-generation antipsychotics, to be the most effective antipsychotic out there, but it’s hardly being used," Susan M. Essock, PhD, from the New York State Psychiatric Institute and Columbia University, New York, New York, told Medscape Medical News at a poster session.

Dr. Susan M. Essock

Up to 30% of people with schizophrenia are potential candidates for clozapine because they have refractory psychotic symptoms that do not respond well to first-line antipsychotics.

Yet only 2% to 3% of people with schizophrenia in the United States, and fewer than 6% in New York State, take the drug, Dr. Essock said.

She and her colleagues used New York State Medicaid data to identify factors associated with the initiation of clozapine compared with other antipsychotic medications.

Their study sample included 7035 Medicaid recipients who had a primary diagnosis of schizophrenia or schizoaffective disorder and who filled a prescription for an antipsychotic medication in 2009 without a fill of that same medication in the prior 90 days.

The researchers found that just 144 patients (2%) started clozapine and that 6891 (98%) started another antipsychotic medication.

The most frequently prescribed agent was aripiprazole, with 1175 prescriptions; closely followed by quetiapine, with 1161 prescriptions; risperidone, with 1127 prescriptions; and long-acting injectables, with 1078 prescriptions.

There were 663 prescriptions for olanzapine, 559 for haloperidol, 333 for ziprasidone, 253 for paliperidone, and 199 for fluphenazine.

The study also found that individuals who started clozapine were more likely to be younger (mean age, 36 ± 12 years vs 44 ± 13 years), male, and white. Patients in state-operated facilities were also more likely to get clozapine than patients in other types of facilities. Patients started on clozapine also had higher Medicaid costs (mean, $58,861 ± $65,367) than those not receiving clozapine ($16,687 ± $27,767).

Clozapine is well known to be the most effective antipsychotic for refractory schizophrenia, so why is its use so low?" Dr. Essock asked. "It is true that you need a blood test to make sure that the patient’s white blood cell count is adequate, but the data show that it is worth it to do this extra test."

Commenting on this study for Medscape Medical News, American Society of Clinical Psychopharmacology president John Kane, from the Albert Einstein College of Medicine and the Zucker Hillside Hospital, Glen Oaks, New York, said, "These are important data in highlighting the underutilization of clozapine. Many more patients could potentially benefit from a trial of the medication that has the best chance of succeeding when others fail. We need to work towards reducing the existing obstacles to wider use of clozapine."

Dr. Essock has disclosed no relevant financial relationships. Dr. Kane reported that he has financial relationships with Astra Zeneca, Boehringer Ingelheim, Bristol-Myers Squibb, Cephalon, Dainippon Sumitomo, Eli Lilly, Esai Inc., H. Lundbeck A/S, Intracellular Therapeutics, Janssen Pharmaceuticals, MedAvante, Merck, Novartis, Otsuka, Pfizer, and Rules Based Medicine.

New Clinical Drug Evaluation Unit (NCDEU) 51st Annual Meeting, sponsored by the American Society of Clinical Psychopharmacology (ASCP). Abstract #63. Presented June 14, 2011.