Hematological and cardiometabolic safety of clozapine in the treatment of very early onset schizophrenia: a retrospective chart review.

OBJECTIVE: There are very few studies in the literature regarding clozapine use in children <13 years of age. In this retrospective chart review, we compared the safety of clozapine--as determined by hematological and cardiometabolic changes - to that of non-clozapine antipsychotics used in the treatment of childhood-onset schizophrenia (COS).

METHODS: The clozapine treatment group (CTG) consisted of 17 COS patients (mean age 10.4 ± 2 years) who were hospitalized in a psychiatric ward between the years 2005 and 2012. The control group consisted of 19 COS patients (mean age 10.1 ± 1.4 years) who were hospitalized in the same ward during the same time period, and were treated with non-clozapine antipsychotics. A retrospective chart review was conducted. Hematological (white blood cells, absolute neutrophil count [ANC], red blood cells, platelets), metabolic (aspartate transaminase, alanine transaminase, triglycerides, total cholesterol, bilirubin) and cardiac (heart rate) values were extracted from the medical charts.

RESULTS: The average follow-up periods for the CTG and the control group were 332.9 ± 200.5 days and 291.7 ± 157 days, respectively. In the CTG, moderate neutropenia (ANC<1500/mm(3)) and mild neutropenia (1500/mm(3)100 beats per minute) at release from the hospital, compared with only one child (5%) in the control group (p=0.006).

CONCLUSIONS: It appears that clozapine use in very early onset schizophrenia is safe. Although hematological adverse effects did occur in our study, the rates were not much higher than those seen in the control group. We found that the hematological abnormalities in the CTG were mostly transient, and that treatment with clozapine can be safely continued or renewed.