ADHD Drugs include Adderall, Concerta, Cylert, Metadate, Methylin, Ritalin and Strattera
RITALIN
Study of Ritalin's Cancer-Causing Potential
An animal study of Ritalin (methylphenidate hydrochloride), 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, according to FDA, which has taken steps to alert health professionals to the possible problem.
The agency has asked the drug's sponsor, Ciba Pharmaceuticals, to include the study findings in the labeling for Ritalin, and to alert prescribers by sending them a Dear Doctor letter. The company complied in late January. FDA also plans to initiate additional follow-up studies, including both animal tests and epidemiological studies in humans using Ritalin.
The agency continues to regard Ritalin as a safe and effective drug, but says the potential risk 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, there has been about a two- to threefold increase in the use of the product.
The agency's actions are based on findings of a draft report by the National Toxicology Program on cancer-causing potential of Ritalin in a study in mice and a study in rats.
The study in rats revealed no cancer-causing activity. The findings in mice included increased rates of noncancerous liver tumors and, in males only, the occurrence of cancerous liver tumors.
FDA considers the studies' results a signal of a weak cancer-causing potential because:
» 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 nonmalignant 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.
» to top
