By H. J. Roberts, M.D., F.A.C.P., F.C.C.P.
E-Mail: HJrobertsmd@aol.com

Posted: 24 June 2006

The Food and Drug Administration (FDA) recently noted the frequency of prolactin-producing pituitary tumors in patients taking risperidone, a drug widely prescribed for schizophrenia and bipolar disorder. 1 Of 64 patients with pituitary tumors receiving anti-psychotics, 48 had been using risperidone.

I have reported (a) the stimulation of prolactin by phenylalanine, of the amino acids in aspartame, 2 and (b) the occurrence of prolactin-secreting pituitary tumors among persons taking aspartame in "diet" products. 3 I also have reviewed the occurrence of brain tumors in persons consuming aspartame products, 4 and I am maintaining a registry thereon.

The manufacturer's web site lists aspartame as an "inactive" ingredient of Risperdal M-Tab orally disintegrating tablets - each 2 mg. tablet contains 0.56 phenylalanine and each 1 mg tablet, 0.28 mg. phenylalanine.

Until this issue is resolved by postmarketing drug surveillance, I would urge physicians to caution patients using this drug to avoid aspartame products, and to prescribe formulations of risperidone that do not contain aspartame.

H. J. Roberts, MD, FACP
Palm Beach Institute for Medical Research
P. O. Box 17799
West Palm Beach, Florida 38416 USA


  1. Seligman, P. cited in The Wall Street Journal, 2005, June 17-A-2
  2. Roberts, HJ, Aspartame Disease: An Ignored Epidemic, West Palm Beach, Sunshine Sentinel Press 2001; 726-729
  3. Ibid 809-810
  4. Roberts, HJ, Does Aspartame Cause Human Brain Cancer? 1991 -4 (Winter ) 231-239

Dr. Roberts can be seen in the Aspartame Documentary, Sweet Misery: A Poisoned World, http:// www.soundandfury.tv , http://www.Amazon.com , and Barnes & Noble (In this film you will hear the testimony of Attorney Ed Johnson who had a pituitary brain tumor from aspartame.)

Aspartame Disease: An Ignored Epidemic, http://www.sunsentpress.com H. J. Roberts, M.D.

His reports can be found on http:// www.wnho.net and http://www.dorway.com

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