96-10836. National Toxicology Program; Availability of Technical Report on Toxicology and Carcinogenesis Studies of Methylphenidate Hydrochloride

[Federal Register Volume 61, Number 85 (Wednesday, May 1, 1996)]
[Notices]
[Pages 19306-19307]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-10836]




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DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Toxicology Program; Availability of Technical Report on 
Toxicology and Carcinogenesis Studies of Methylphenidate Hydrochloride

    The HHS' National Toxicology Program announces the availability of 
the NTP Technical Report on the toxicology and carcinogenesis studies 
of methylphenidate hydrochloride. Methylphenidate hydrochloride is a 
drug used in the treatment of narcolepsy and attention deficit 
hyperactivity disorders.

    Toxicology and carcinogenicity studies were conducted by 
administration of methylphenidate hydrochloride in feed to groups of 70 
F344/N rats of each sex at doses of 0, 100, 500, or 1,000 ppm and to 
groups of 70 B6C3F1 mice of each sex at doses of 0, 50, 250, or 
500 ppm.

    Under the conditions of these 2-year feed studies, there was no 
evidence of carcinogenic activity 1 of

[[Page 19307]]

methylphenidate hydrochloride in male or female F344/N rats receiving 
100, 500, or 1,000 ppm. There was some evidence of carcinogenic 
activity in male and female B6C3F1 mice, based on the occurrence 
of hepatochellular neoplasms.
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    \1\ The NTP uses five categories of evidence of carcinogenic 
activity observed in each animal study: two categories for positive 
results (``clear evidence'' and ``some evidence''), one category for 
uncertain findings (``equivocal evidence''), one category for no 
observable effect (``no evidence''), and one category for studies 
that cannot be evaluated because of major flaws (``inadequate 
study'').
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    Treatment of female rats with methylphenidate hydrochloride was 
associated with a decrease in the incidence of mammary gland 
fibroadenomas. Administration of methylphenidate hydrochloride to male 
and female mice resulted in increased incidence of eosinophilic foci in 
the liver.
    Questions or comments about the Technical Report should be directed 
to Central Data Management at P.O. Box 12233, Research Triangle Park, 
NC 27709 or telephone [phone].
    Copies of Toxicology and Carcinogenesis Studies of Methylphenidate 
Hydrochloride (CAS No. 298-59-9) (TR-439) are available without charge 
from Central Data Management, NIEHS, MD E1-02, P.O. Box 12233, Research 
Triangle Park, NC 27709; telephone [phone].

    Dated: March 27, 1996.
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 96-10836 Filed 4-30-96; 8:45 am]
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