RISK OF OVERDOSE — RIVASTIGMINE TRANSDERMAL (EXELON) PATCH FOR ALZHEIMER’S DISEASE

      Worst Pills, Best Pills Newsletter Article, September 2010

The U.K. and Canadian equiva­lents of the Food and Drug Ad­ministration (FDA) recently issued warnings concerning serious side effects related to the misuse of the rivastigmine patch that have resulted in overdose.

The rivastigmine patch (EXELON) was approved by the FDA in July 2007 for the treatment of mild to moderate Alzheimer’s disease and mild to moderate dementia as­sociated with Parkinson’s disease. Rivastigmine also is available in an oral dosage form. For a long time, we have advised Worst Pills, Best Pills News readers not to use the oral form of this drug because of the lack of any important benefit combined with the high incidence of side effects. The FDA physician who reviewed this older version of the drug stated in 2000, before its approval, “I recom­mend that this application not be approved on the grounds that the risks of using the drug outweigh the possible benefits.”

Health Canada, the Canadian equivalent of the FDA, reported that as of July 31, 2009, a total of 129 cases of medication errors or misuse, including two fatal cases, had been reported for the rivastigmine patch worldwide. The most frequently reported causes of overdose are failure to remove the patch before applying a new one and application of more than one patch at the same time.