The diabetes drug metformin -- especially with a
diet/exercise regimen -- largely
reverses the weight-gain side effect of antipsychotic drugs.
Antipsychotic medications -- especially the newer atypical antipsychotics --
are effective treatments for a number of psychotic disorders and severe
behavioral disturbances. But they have a dreaded side effect: significant weight gain .
Weight gain is a major reason why people suffering from psychosis die up to
30 years sooner than the general population. Recent studies have suggested that
lifestyle intervention -- helping psychotic patients improve their diets and
increase their exercise levels -- helps reduce weight gain.
Now a study of 128 newly diagnosed schizophrenic patients in China suggests
that the older diabetes drug metformin has a dramatic effect on weight gain
associated with antipsychotics. Ren-Rong Wu, MD, of Central South University in
Changsha, China, and colleagues report the findings in the January 9/16 issue
of The Journal of the American Medical Association.
"Lifestyle intervention and metformin alone and in combination
demonstrated efficacy for antipsychotic-induced weight gain," Wu and
colleagues conclude. "Lifestyle intervention plus metformin showed the best
effect on weight loss . Metformin alone was
more effective ... than lifestyle intervention alone."
The patients in the study had all gained more than 10% of their body weight
after beginning antipsychotic treatment with Clozaril, Zyprexa , Risperdal , or sulpiride (used
in Asia and Europe but not in North America).
The patients were randomly assigned treatment with metformin alone,
metformin plus diet/exercise, inactive placebo alone, or inactive placebo plus
After 12 weeks:
- Those assigned to placebo alone gained 6.8 pounds. Their waist size grew by
nearly an inch.
- Those assigned to placebo plus diet/exercise lost 3.1 pounds. Their waist
size shrank by a tiny fraction of an inch.
- Those assigned to metformin alone lost 7.1 pounds. Their waist size shrank
by a half-inch.
- Those assigned to metformin plus diet/exercise lost 10.4 pounds. Their
waist size shrank by nearly an inch.
All of the patients in the study had only recently begun low-dose
antipsychotic treatment; none had yet become obese . It's not yet clear
whether obese patients or those on long-term, high-dose antipsychotic treatment
will obtain similar results from metformin treatment.
By Daniel DeNoon
Reviewed by Louise Chang
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