Agranulocytosis: incidence and risk factors.
The use of clozapine has been limited by the risk of agranulocytosis. The cumulative incidence of agranulocytosis is 0.80% after 1 year and 0.91% after 1 1/2 years. Risk is greatest during the first 3 months of treatment and greater among women and the elderly. White-cell counts tend to spike upward before the occurrence of agranulocytosis. The occurrence of a white-cell count spike of > or = 15% above the previous count predicts development of agranulocytosis within 75 days (risk ratio = 3.02; 95% confidence interval, 1.38-6.57). Our results indicate that hematologic monitoring is necessary and effective. They also suggest that the frequency of monitoring could be reduced after the initial period of maximal risk.
Hillside Hospital, Long Island Jewish Medical Center, Glen Oaks, N.Y. 11004.
J M
JM
Alvir
J A
JA
Lieberman
D000328:Adult; D000367:Age Factors; D000380:Agranulocytosis / Q000139:chemically induced / Q000453:epidemiology*; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use; D015331:Cohort Studies; D016001:Confidence Intervals; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D015994:Incidence; D007958:Leukocyte Count; D008297:Male; D009504:Neutrophils; D011358:Product Surveillance, Postmarketing; D012307:Risk Factors; D012559:Schizophrenia / Q000188:drug therapy; D012737:Sex Factors; D014481:United States / Q000453:epidemiology
D003024:Clozapine