Metformin helps with antipsychotic weight loss
By Karla Gale
NEW YORK (Reuters Health) - Treatment with metformin or lifestyle changes promoting exercise and a healthy diet are both effective in reversing the weight gain associated with antipsychotic medications, according to a clinical trial conducted in China. However, a combination of the two approaches is even better.
Metformin, sold under various trade names such as Glucophage, is primarily used to lower blood sugar in patients with type 2 diabetes.
Dr. Jing-Ping Zhao and associates at the Mental Health Institute of the Second Xiangya Hospital in Changsha note that by lowering glucose production in the liver, metformin prevents weight gain and decreases insulin resistance.
However, its effect on the metabolic complications of antipsychotic medication has not been established, the researchers point out in the Journal of the American Medical Association.
Zhao's group enrolled 128 adults with schizophrenia who gained more than 10 percent of their body weight after taking an antipsychotic drug for 1 year. They were randomly assigned to receive metformin, placebo, lifestyle interventions plus metformin, or lifestyle interventions plus placebo.
The lifestyle intervention included an educational program, the American Heart Association's step 2 diet and daily moderate exercise for at least 30 minutes.
"To keep patients with schizophrenia compliant with treatment, they all had to be under the care of their parents or another adult caregiver," Zhao told Reuters Health.
The subject's average body mass index was 24.5 at the beginning of the study and the average weight was 64.6 kg (142.4 lbs).Body mass index (BMI) is the ratio of height to weight commonly used to classify individuals as underweight, overweight or in a normal weight range. A BMI of 24.5 is at the top end of the normal range.
After 12 weeks, all measured outcomes had worsened in the placebo group, including a weight gain of 3.1 kg (6.8 lbs).
In the metformin group, all outcomes had improved; subjects lost an average of 3.2 kg (7.1 lbs). Subjects in the lifestyle intervention group lost 1.4 kg (3.1 lbs).
However, the benefits of combined treatment were significantly greater than those achieved by either intervention alone. Weight loss in the combined treatment group averaged 4.7 kg (10.4 lbs).
"We recommend that lifestyle intervention plus metformin be considered first for those with weight gain. If patients cannot tolerate or adhere poorly to lifestyle intervention, they should consider metformin alone," Zhao advised.
"Of course, the safety of metformin must be ensured," Zhao stressed.
The team is currently engaged in the next stage of their research, he added. "We are studying the efficacy of long-term metformin and lifestyle intervention, and different doses of metformin, on antipsychotic-induced weight gain."
SOURCE: Journal of the American Medical Association for January 9-16, 2008.