From conventional to atypical antipsychotics and back: dynamic processes in the diffusion of new medications.
OBJECTIVE
Between 1994 and 1997, the Food and Drug Administration approved three new atypical antipsychotic medications for the treatment of schizophrenia. The authors tracked prescription patterns for these medications, an atypical antipsychotic approved in 1989, and conventional neuroleptics in the Department of Veterans Affairs (VA) to determine how the new drugs have diffused in a national health care system.


METHODS
Pharmacy claims data were collected for all patients with a diagnosis of schizophrenia in the VA. Patients who received stable 3-month prescriptions of any antipsychotic medication were followed over fiscal year 2000 to determine how often they were switched to another drug, how much time elapsed before they were switched, the drug to which they were switched, and whether they subsequently switched back to the original drug.


RESULTS
Of the 21,873 patients with schizophrenia who had stable 3-month prescriptions of any antipsychotic medication, 5,426 (25%) had their medications switched during the next year. Half of these patients (N=2,708) switched back to their original drug, usually within 30 days. Patients who had stable prescriptions of clozapine were the least likely to be switched (18%), and patients who had stable prescriptions of quetiapine were the most likely to be switched (37%). When medications were switched, 35% of the patients were switched to olanzapine; only 1% were switched to clozapine, and only 14% were switched to quetiapine.


CONCLUSIONS
Pharmacotherapy for schizophrenia is a dynamic process. One-quarter of patients with stable antipsychotic drug regimens had their medication changed within 1 year. Quetiapine was the least prescribed of the newer drugs. These results suggest that it is important that all of these medications are included in formularies.
Department of Psychiatry, Yale School of Medicine, CT, USA.
Douglas L
DL
Leslie
Robert A
RA
Rosenheck
D000553:Ambulatory Care; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001569:Benzodiazepines; D003024:Clozapine / Q000008:administration & dosage / Q000627:therapeutic use; D003987:Dibenzothiazepines / Q000008:administration & dosage / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D004363:Drug Utilization; D005260:Female; D006787:Hospitals, Veterans / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077152:Olanzapine; D010890:Pirenzepine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000627:therapeutic use; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D000069348:Quetiapine Fumarate; D012559:Schizophrenia / Q000188:drug therapy*; D013997:Time Factors; D014481:United States; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data
D014150:Antipsychotic Agents; D003987:Dibenzothiazepines; D001569:Benzodiazepines; D000069348:Quetiapine Fumarate; D010890:Pirenzepine; D003024:Clozapine; D000077152:Olanzapine