A University of California researcher says that the findings of a new study provide proof that zinc-based Zicam nasal products, which were recalled last year, may cause some people to lose their sense of smell.
The research was published in this month’s issue of the medical journal Archives of Otolaryngology – Head & Neck Surgery. It is the first study to find a causal link between Zicam and loss of smell, a condition known as anosmia. Proving the suspected link has been difficult, since the common cold, which Zicam is used to treat, can also sometimes cause anosmia.
On June 15, 2009, the FDA indicated that it had identified at least 120 reports of loss of smell with Zicam Cold Remedy Nasal Gel, Zicam Cold Remedy Nasal Swabs and Zicam Cold Remedy Swabs Kids Size. Within hours of the warning, Matrixx Initiatives issued a Zicam recall.
In the aftermath of the recall, FDA inspectors discovered 800 reports of Zicam problems that Matrixx Initiatives failed to forward to the agency, in violation of federal regulations.
Matrixx Initiatives has continued to defend their products, claiming that Zicam does not cause anosmia. When the FDA asked them why they had not reported the hundreds of claims by Zicam users, company officials said they did not believe they needed to be reported since they did not believe anosmia from Zicam was possible.
The latest study is a causality analysis that looked at 25 patients at the University of California, San Diego, Nasal Dysfunction Clinic. All of the patients complained of acute-onset anosmia after they had used a Zicam nasal product.
Since actually testing a product on human subjects that could cause them to lose their sense of smell and taste would be unethical, lead study author Dr. Terence M. Davidson used what is known as the Bradford Hill criteria to determine causation in the 25 cases of patients who already suffered from anosmia. It is a statistical method used to establish a cause-and-effect link between environmental exposure and contracting a disease. Davidson said that the criteria supports a causal link between zinc-based homeopathic medications and anosmia.
Matrixx Initiatives faces a number of Zicam lawsuits that allege the company knew the products were dangerous and continued to market them anyway. The company also faces Zicam class action lawsuits from investors who say that the company falsely represented its products by hiding the anosmia complaints. The SEC is also investigating the company’s actions.
Last October, the U.S. Judicial Panel on Multidistrict Litigation consolidated the federal Zicam litigation for pretrial proceedings in the District of Arizona. All of the lawsuits over Zicam contain similar allegations that zinc gluconate, the single active ingredient in nasal Zicam cold remedies, is toxic to the tissue inside the nose and can cause damage to a user’s ability to smell, detect odors or taste.