Denture Cream Zinc Poisoning Risks Finally Get FDA Notice

The potential risk of denture cream zinc poisoning has finally been acknowledged by the U.S. Food & Drug Administration (FDA). In a letter dated February 23, the agency has asked denture cream manufacturers to take steps to mitigate the risk of zinc poisoning from their products. The FDA also writes that it is considering issuing a communication on its website to warn consumers and health care providers about the possible risk of neurological injuries from excessive use of zinc-containing denture cream.

Anyone who is a regular reader of this blog already knew that zinc in products like Fixodent, and until recently, Super Poligrip could cause neurological damage if used in excess. As we’ve reported on numerous occasions, the first study to find a link between zinc-containing denture cream and a neurological injury was published in August 2008 in the peer reviewed journal “Neurology.” That study reported on four patients suffering from neuropathy and other neurological symptoms typical of zinc poisoning and copper depletion (a consequence of zinc poisoning.) The article specifically linked excessive exposure to zinc in denture cream to “profound neurologic disease” in the patients reviewed.

Since that study was published, scores of people have sued the makers of Super Poligrip and Fixodent denture creams over their neurological injuries. Those denture cream zinc poisoning lawsuits are now part of a multidistrict litigation in the United States District Court for the Southern District of Florida, Miami Division (MDL No. 2051).

Since being named in lawsuits, the makers of zinc denture creams have even taken some action to address the health threat posed by their products. Last February, GlaxoSmithKline announced it would stop the manufacture, distribution and advertising of three Super Poligrip products that contained zinc. In a statement posted on its website, Glaxo said it was reformulating the Super Poligrip products as a precautionary measure to minimize any potential risks to consumers.

Procter & Gamble, the maker of Fixodent, hasn’t been willing to go that far, but a month after Glaxo made its announcement, the company did begin cautioning consumers about zinc in Fixodent denture creams on its website. At the same time, Procter & Gamble also began shipping Fixodent with updated label instructions on how to apply the product. The zinc, however, remains in Fixodent.

Now, more than two years after the “Neurology” study was published, the FDA is finally taking notice. In its February 23 letter to denture cream manufacturers, the agency says it has “received numerous reports of adverse events related to the use of denture adhesives, and that literature and research “suggests zinc contained in some denture adhesives may be a contributing factor in these adverse events.”

The letter continues:

“Consumers using denture adhesives have reported local and systemic symptoms consistent with zinc toxicity that may be associated with use of the product. Symptoms may include: myeloneuropathy of the extremities and blood dyscrasias.

Consumers most at risk include people using excessive amounts of these products over extended periods of time; people with poor fitting dentures; and people who are unable to read or understand product labeling.”

The FDA asks denture cream manufacturers to consider taking several steps to address the risk of zinc toxicity posed by their products. These steps include: Performing risk analysis of their denture cream labels to assess how the zinc poisoning risk can be mitigated; conducting studies to assess consumer understanding of labeling and the potential for misuse of zinc containing denture creams; modifying labels to state products contain zinc and define maximum safe usage in easily understood terms; and replacing zinc with an ingredient that presents less health risks in situations of overuse.

While it is good to see the FDA finally taking some kind of action to address the dangers of zinc-containing denture creams, it is disturbing that it took the agency so long to act. Despite the publication of the “Neurology” study, and the litigation involving these products, many consumers are still unaware that many denture creams contain zinc, let alone that they are dangerous if used in excess. It’s impossible to know how many Fixodent and Super Poligrip users could have been spared the pain and suffering of serious neurological injury had the FDA acted sooner.