A prospective study of impairment in glucose control caused by clozapine without changes in insulin resistance.
OBJECTIVE
This prospective study examines the effect of clozapine on glucose control and insulin sensitivity.


METHODS
Glucose homeostasis was measured in nine female and 11 male patients with schizophrenia (mean age=30.5 years, SD=7.4) before clozapine treatment and after a mean of 2.5 months (SD=0.95) of clozapine treatment. Oral glucose tolerance and insulin levels were measured. Insulin resistance level was measured by the homeostasis model assessment.


RESULTS
Eleven (55%) of the patients developed abnormal glucose control; the mean age of these patients was 30.2 (SD=7.1), and five were women. Patients' insulin resistance at baseline (mean insulin resistance level=3.88, SD=2.93) was unaffected by clozapine. Mean fasting and 2-hour glucose levels significantly increased by 0.55 mmol/liter and 1.4 mmol/liter, respectively. There was no correlation between change in body mass index and change in fasting glucose levels.


CONCLUSIONS
Clozapine impairs glucose control within 4 months of treatment, independent of changes in insulin sensitivity and body mass index.
Howes
Oliver D
OD
Division of Psychological Medicine, Insitute of Psychiatry, London, UK. sphaoah@iop.kcl.ac.uk
Bhatnagar
Ajay
A
Gaughran
Fiona P
FP
Amiel
Stephanie A
SA
Murray
Robin M
RM
Pilowsky
Lyn S
LS
D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects*; D001786:Blood Glucose / Q000187:drug effects*; D015992:Body Mass Index; D003024:Clozapine / Q000009:adverse effects*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000139:chemically induced*; D011446:Prospective Studies; D012559:Schizophrenia / Q000188:drug therapy*; D012720:Severity of Illness Index
D014150:Antipsychotic Agents; D001786:Blood Glucose; D003024:Clozapine