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This is the retyped text of a letter from Abbott Laboratories Pharmaceutical Products
         Division. Contact the company for a copy of any referenced enclosures.





December, 1996

Dear Doctor:

This communication is to advise you of a labeling change for Cylert (pemoline, Abbott). A recent review of postmarketing experience with Cylert disclosed ten reports from the U.S. of acute liver failure in children, with additional reports of liver failure in adults and in children from foreign countries.

Based on discussions with the Food and Drug Administration (FDA), Abbott Laboratories has modified the current product labeling to include a boxed warning describing liver failure and to indicate that Cylert should not ordinarily be considered as first line drug therapy for Attention Deficit Hyperactivity Disorder (ADHD). Related changes have been made to the Precautions/Laboratory Tests and the Adverse Reactions/Hepatic subsections of labeling. A copy of the revised package insert is included for your review. The following is the text of the boxed warning.

     Because of its association with life threatening hepatic failure, CYLERT should not ordinarily be considered as first line drug therapy for ADHD (see INDICATIONS AND USAGE).

     Since CYLERT's marketing in 1975, 13 cases of acute hepatic failure have been reported to the FDA. While the absolute number of reported cases is not large, the rate of reporting ranges from 4 to 17 times the rate expected in the general population. This estimate may be conservative because of under reporting and because the long latency between initiation of CYLERT treatment and the occurence of hepatic failure may limit recognition of the association . If only a portion of actual cases were recognized and reported, the risk could be substantially higher.

     Of the 13 cases reported as of May 1996, 11 resulted in death or liver transplantation, usually within four weeks of the onset of signs and symptoms of liver failure. The earliest onset of hepatic abnormalities occurred six months after initiation of CYLERT. Although some reports described dark urine and nonspecific prodromal symptoms (e.g., anorexia, malaise, and gastrointestinal symptoms), in other reports it was not clear if any prodromal symptoms preceded the onset of jaundice. It is also not clear if the recommended baseline and periodic liver function testing are predictive of these instances of acute liver failure. CYLERT should be discontinued if clinically significant dysfunction is observed during its use. (see PRECAUTIONS).

If you have any questions, please contact our Medical Services Department at 1-800-633-9110.


David Pizzuti, M.D.
Divisional Vice President
Medical Affairs and Pharmaceutical Ventures

Enclosure: Cylert (pemoline) Product Information, Abbott Laboratories

Abbott Laboratories
Pharmaceutical Products Division
200 Abbott Park Road
Abbott Park, IL 60064-3537

This is a reprinted, mirrored version of the original as posted on the FDA's website.
Placed here as a courtesy for the visitors of this websites pages to continue to provide this
warning if the original becomes expired after a certain period of time.
The original may be view at

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