Olanzapine induces insulin resistance: results from a prospective study.
BACKGROUND
The aim of this study was to compare glucose metabolism in patients with schizophrenia receiving olanzapine with that in control subjects.


METHODS
We conducted a prospective, controlled, open study comparing body weight, fat mass, and indices of insulin resistance/ sensitivity in 10 olanzapine-treated patients with ICD-10 schizophrenia (olanzapine dose range, 7.5-20 mg/day) with those of a group of 10 mentally and physically healthy volunteers. Weight, fat mass, and indices of insulin resistance/sensitivity were assessed over individual 8-week observation periods from November 1997 to October 1999.


RESULTS
Fasting serum glucose and fasting serum insulin increased significantly in the olanzapine-treated patients (p =.008 for glucose and p =.006 for insulin). The homeostasis model assessment (HOMA) index for beta cell function did not change significantly in the olanzapine-treated patients, whereas the HOMA index for insulin resistance did increase (p =.006). In the control group, these parameters were stable. A significant increase in body weight (p =.001) and body fat (p =.004) was seen in patients treated with olanzapine, while the control group showed no significant changes.


CONCLUSIONS
This study indicates that the disturbances in glucose homeostasis during antipsychotic treatment with olanzapine are mainly due to insulin resistance. However, beta cell function remains unaltered in olanzapine-treated patients. We conclude that treatment with some second-generation antipsychotic drugs may lead to insulin resistance.
Ebenbichler
Christoph F
CF
Department of Medicine, University of Innsbruck, Innsbruck, Austria. Christoph.Edenbichler@uibk.ac.at
Laimer
Markus
M
Eder
Ursula
U
Mangweth
Barbara
B
Weiss
Elisabeth
E
Hofer
Alex
A
Hummer
Martina
M
Kemmler
Georg
G
Lechleitner
Monika
M
Patsch
Josef R
JR
Fleischhacker
W Wolfgang
WW
D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001569:Benzodiazepines; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D007515:Islets of Langerhans / Q000187:drug effects; D008297:Male; D000077152:Olanzapine; D010890:Pirenzepine / Q000009:adverse effects* / Q000031:analogs & derivatives* / Q000627:therapeutic use; D011446:Prospective Studies; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy*
D014150:Antipsychotic Agents; D001786:Blood Glucose; D001569:Benzodiazepines; D010890:Pirenzepine; D000077152:Olanzapine