Metformin for prevention of weight gain and insulin resistance with olanzapine: a double-blind placebo-controlled trial.
OBJECTIVE
To assess whether metformin prevents body weight gain (BWG) and metabolic dysfunction in patients with schizophrenia who are treated with olanzapine.


METHODS
Forty patients taking olanzapine (10 mg daily) were randomly allocated to a metformin (n = 20; 850 to 1700 mg daily) or placebo (n = 20) group in a 14-week double-blind study. Waist circumference (WC), BWG, body mass index (BMI) fasting glucose, insulin, and lipids were evaluated at baseline and at Weeks 7 and 14 of treatment.


RESULTS
At Week 14, BWG (kg) was similar in the metformin group (5.5 kg) and the placebo group (6.3 kg), P = 0.4. There were no differences between the changes in BMI, WC, glucose, insulin, insulin resistance index (HOMA-IR), and plasma lipid levels observed in the treatment group and the placebo group; however, glucose levels decreased significantly after metformin administration (P = 0.02). The HOMA-IR decreased significantly in both groups, but 3 subjects from the placebo group developed fasting glucose levels greater than 5 mmol/L. After taking metformin, triglyceride levels increased, but the cholesterol profile improved significantly.


CONCLUSIONS
Metformin did not prevent olanzapine-induced BWG. While some lipid parameters worsened during placebo, the HOMA-IR improved in both the placebo and the metformin groups. Carbohydrate metabolism impairment was not systematically observed during short-term olanzapine administration.
Baptista
Trino
T
Department of Physiology, Los Andes University Medical School, Mérida, Venezuela. trinbap@yahoo.com
Martínez
Jessan
J
Lacruz
Anny
A
Rangel
Nairy
N
Beaulieu
Serge
S
Serrano
Ana
A
Arapé
Yinet
Y
Martinez
Maritza
M
de Mendoza
Soaira
S
Teneud
Luis
L
Hernández
Luis
L
D000328:Adult; D000886:Anthropometry; D014150:Antipsychotic Agents / Q000009:adverse effects*; D001569:Benzodiazepines / Q000009:adverse effects; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000139:chemically induced; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D009765:Obesity / Q000139:chemically induced* / Q000517:prevention & control*; D000077152:Olanzapine; D012559:Schizophrenia / Q000188:drug therapy*; D015430:Weight Gain / Q000187:drug effects*
D014150:Antipsychotic Agents; D007004:Hypoglycemic Agents; D001569:Benzodiazepines; D008687:Metformin; D000077152:Olanzapine