Study Links Zinc Cold Remedies to Loss of Smell

A new study has linked the use of nasal remedies containing zinc gluconate with the loss of the sense of smell.

Zinc gluconate is a dietary supplement marketed as a homeopathic remedy to shorten the duration of the common cold.

Study authors Terence M. Davidson, MD and Wendy M. Smith, MD, of the University of California, San Diego, evaluated the relationship between over-the-counter intranasal zinc gluconate therapy and anosmia. Their study results showed that intranasal zinc gluconate therapy causes hyposmia, a reduced ability to smell and to detect odors, and anosmia the total loss of smell.

The study appears in the July 2010 issue of the Archives of Otolaryngology – Head & Neck Surgery.

In June of 2009, the U. S. Food and Drug Administration (FDA) advised consumers not to use Zicam Cold Remedy Nasal Gel or Zicam Cold Remedy Nasal Swabs, which contained zinc gluconate, due to more than 130 reports of loss of sense of smell associated with the use of the three Zicam products. The FDA issued Matrixx Initiatives, maker of the Zicam products, a warning letter telling the company that it could not market the products without FDA approval.

“Loss of sense of smell is a serious risk for people who use these products for relief from cold symptoms,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research (CDER). “We are concerned that consumers may unknowingly use a product that could cause serious harm, and therefore we are advising them not to use these products for any reason.”

The FDA warned that loss of the sense of smell may cause serious problems, such as failing to smell smoke, a gas leak, or spoiled food. In addition, loss of the sense of smell is often linked with a loss of the sense of taste. People who cannot taste could unintentionally eat spoiled food and not appreciate flavors, and lose much of the pleasure of eating.

In response to the FDA’s June 2009 warning letter, Matrixx Initiatives said the company “vigorously disagrees with the FDA’s allegations” and that the FDA’s actions were “unwarranted,” but agreed issue a voluntary recall and to withdraw the products from the market.

According to Matrixx, the company sold more than 35 million retail units, representing over 1 billion doses, since they first introduced Zicam Cold Remedy intranasal products to the market in 1999. These products constituted approximately 40% of the Company’s net sales in 2009.
The FDA allegations in 2009 were not the first report of Matrixx Initiatives’ Zicam Cold Remedy Nasal Gel and Swabs affecting consumer’s sense of smell. According to the company’s own literature, allegations of such adverse effects from their zinc gluconate nasal products began in 2003 and continued for years before the FDA issued the warning letter. In 2006, the company agreed to settle 340 lawsuits resulting from their products’ adverse effects on the sense of smell at a cost of about $12 million and then continued to sell the products without warning consumers of the danger.

Matrixx Initiatives said in a January 2007 release, “The decision by Matrixx to settle some lawsuits was a business and economic decision. It was not based on any perception that the claims are legitimate.”

The company cited two studies, one from 2000 and another from 2003, it says proved the effectiveness of the products.

However, a 2006 study of the effectiveness of such zinc nasal treatments found no effect on the common cold. “We contend that it is unethical to introduce any potentially permanent anosmia-inducing agent such as zinc or other heavy metals into the interior of the nose in a manner that could result in contact with the olfactory region to treat a temporary discomfort such as a common cold or allergy,” the study said. “We found no reason to recommend intranasal zinc gluconate or zinc orotate lozenges in treating common colds.”

Read When every scent disappeared from my world, a woman’s account of the adverse effects she suffered from Zicam in 2005.
The study released this month linking nasal remedies containing zinc gluconate with the loss of smell is important because it is the first study to find a definite link. In the Zicam cases that have come before the court, judges have found little scientific evidence to support the claim that zinc-containing Zicam nasal products caused loss of smell.

Despite Matrixx Initiatives’ withdrawal and recall of Zicam Cold Remedy Nasal Gel and Zicam Cold Remedy Nasal Swabs, and the fact that it is illegal to sell recalled products, consumers can still find these products in the marketplace.

Very few people realize what it’s like to lose their sense of smell, and this is the time for people to stop for a moment and see how much smell means to them," Dr. Davidson told AOL Health. "It’s Christmas, loved ones, pines trees and food. It’s one of our most basic senses."