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Cytogenetic Effects in Children Treated with Methylphenidate

Randa El-Zein, MD, PhD, Department of Epidemiology, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd, #189, Houston, TX 77030, (713) 745-2539, donna.wright@apha.org

In recent years there has been a surge in the use of methylphenidate (Ritalin) for the treatment of attention deficit/hyperactivity disorder (ADHD). However, there is a paucity of information on whether this drug poses any potential health hazards for humans. In view of the provocative findings of a comprehensive two-year carcinogenicity study in laboratory animals that indicated a significant increase in hepatocellular tumors in mice treated with methylphenidate, we investigated whether this central nervous system stimulant produces cytogenetic abnormalities in patients at therapeutic levels. In a population composed of twelve children treated with methylphenidate for ADHD, we analyzed three cytogenetic endpoints in peripheral blood lymphocytes obtained before and three months after treatment with this drug. In all participants, treatment with methylphenidate was associated with a significant 3-, 5- and 2.5-fold (P<0.05) increase in frequencies of chromosome aberrations, sister chromatid exchanges and micronuclei, respectively. The unambiguous results of this study, coupled with the positive animal cancer bioassay data, provide strong evidence that this drug induces genetic damage, not only in animals but in humans as well. These findings warrant immediate attention to the need for further investigations of the possible health effects of methylphenidate, especially in view of the well-documented relationship between elevated frequencies of chromosome aberrations and increased cancer risk.

Learning Objectives:

Keywords: Children,

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.

Latebreaking Developments in Public Health

The 132nd Annual Meeting (November 6-10, 2004) of APHA