September 20, 2005

Amantadine Curbs Antipsychotic Weight Gain?

Amantadine (Symmetrel) is normally used to treat Parkinson's disease, but a study has found that taking it while taking olanzapine (Zyprexa) may stabilize the weight gain associated with this drug. "They therefore investigated the effect that amantadine, a dopamine agonist, had on the weight of 21 patients with schizophrenia. It has been postulated that the drug can stabilize weight due to its ability to decrease prolactin and thereby influence gonadal and adrenal steroids.

The researchers randomly assigned the 21 adults, who had all gained at least 5 lb following 1 to 44 months of treatment with olanzapine, to take amantadine (n=12) or placebo (n=9) in addition to olanzapine for 12 weeks" (

All of the subjects had a body mass index of at least 25 kg/m2, with the average being 32.9 kg/m2. Those taking amantadine gained less weight during the study and participants lost an average of 0.8 lbs with their body mass index reducing by 0.07 kg/m2. The controls taking a placebo gained an average of 8.7 lbs, and their body mass index went up by 1.24 kg/m2. In all, 67% of those taking amantadine either loss weight or had their weight stabilized. Only 22% of those taking placebo had these effects.

The researchers in this study noted that amantadine was best used as a preventive measure of weight gain, rather than to lose large amounts of weight already gained by taking olanzapine. Taking amantadine concurrently with antipsychotics should be studied further.

SOURCE: Amantadine may counteract antipsychotic-induced weight gain. September 20, 2005.

This research article was published in Am J Psychiatry 2005; 162: 1744–1746

You can learn more about Amantadine/Symmetrel at

Another article on our website about antipsychotic weight gain, can be found here.

Check out this interview with David Henderson, MD on antipsychotic weight gain on Medscape


Austin, Texas:
I am trying to find a MHMRA doctor who is knowledgeable about Amantadine, and who will prescribe it for my daughter. Any hints or suggestions very welcome!

Posted by: Deborah Poisot at January 10, 2006 12:22 PM

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