ANSWERS
01/12/1996

<TITLE> RITALIN STUDIES </TITLE>
<PRE>

T96-4                                          Don McLearn 
Jan. 12, 1996                                  (301) 827-6242


RITALIN STUDIES

     FDA has taken steps to alert the health care community that
an animal study of Ritalin, a stimulant widely prescribed for
children with attention deficit hyperactivity disorder (ADHD),
has produced a "weak signal" that the drug may have the potential
to cause cancer.
     The agency continues to regard Ritalin as a safe and
effective drug.  However, the signal indicates a potential risk
that needs to be considered and further studied because of the
increasing and often long-term use of Ritalin in children. In the
last five years, the use of the product has increased
approximately two-to-threefold.
     The agency's actions are based on findings in a draft report
on two two-year studies by the National Toxicology Program (NTP)
on cancer-causing potential of Ritalin in mice and rats.
     The study in rats revealed no cancer-causing activity.  The
findings in mice included increased rates of a non-cancerous
liver tumor (hepatocellular adenomas) and, in males only, the
occurrence of malignant liver tumor (hepatoblastomas).
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                                        Page 2, T96-4, Ritalin
     FDA considers the results of the studies a signal of a weak
cancer-causing potential for this drug, based on the following:
     -- The positive findings were seen in one species of rodent
(the mouse) and in only one organ -- the liver -- which is known
to be particularly likely to develop tumors to a wide variety of
stimuli.
     -- The increased rates were seen primarily in non-malignant
tumors.
     -- There was no increase in mortality associated with the
tumors.
     The agency also noted that animal studies do not necessarily
reflect human findings. The kind of liver tumor found in mice is
extremely rare in people, and its occurrence in recent years has
not increased despite the increased use of Ritalin.
     The agency has asked the drug's sponsor to include the
positive findings in the labeling for Ritalin, and to alert
prescribers to the "weak signal" by sending them a Dear Doctor
letter. FDA also plans to initiate additional followup studies,
including both animal tests and epidemiological studies in humans
using Ritalin.
     Ritalin is manufactured by Ciba Pharmaceuticals, division of
Ciba-Geigy Corp. in Summit, N.J.
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