The research isn't conclusive, but an FDA warning indicates the potential of loss of sense of smell when using certain Zicam products.
The warning, issued on June 16, 2009, states that all consumers should discontinue using all intranasal products made by Zicam that include zinc. At the time of the issued warning, the FDA had received more than 130 complaints that the following Zicam products caused a loss of the sense of smell:
- Zicam Cold Remedy Nasal Gel (15ml)
- Zicam Cold Remedy Swabs (20 count)
- Zicam Cold Remedy Swabs, Kids Size (20 count)
At the same time, the FDA sent a letter to the products' manufacturer -- Matrixx Initiatives, Inc. -- advising that these products cannot be marketed without FDA approval, which they do not have (the products are currently marketed as homeopathic medications). In addition, the products have not had adequate warnings about the risk of the loss of sense of smell on their packaging and labels.
This warning is based on consumers' reports only. Those who believe they lost their sense of smell after using these products should first see their healthcare professional and then contact the FDA.
Notable Research Related to ZicamSafety
Two notable studies have been performed and published that relate to the issue of anosmia (loss of the sense of smell). The first was performed by Dr. Burton Slotnick and tested the effect of zinc sulfate, which is different from the zinc gluconate in Zicam, on the smell center in mice.
That study found that there was a temporary loss of the sense of smell when mice were given high doses of zinc sulfate.
The second study was also performed by Dr. Slotnick and a group of researchers, but was supported in part by a grant from Matrixx. This more recent study tested the effect of zinc gluconate, the active ingredient in Zicam, on mice.
The results of that study showed that there was only a partial and temporary loss of the sense of smell in mice when given extremely large doses (much higher than the normal dose for humans). However, the damage was reversed within a couple of weeks.
It is important to point out that both of these studies were performed on mice; we must be cautious when applying results of testing on animals to humans. Because there have been no large-scale studies examining this matter performed on humans, we cannot say conclusively that the product either causes or does not cause anosmia in humans.
Efficacy
Neither Zicam nor Cold-Eeze is regulated by the FDA, yet both claim to shorten the duration of the common cold. The manufacturer claims that this was proven in a study by the Cleveland Clinic, a research facility. However, according to the study, the effects of zinc nasal spray on the common cold are still inconclusive.
Previous HeadlinesHundreds of people were involved in the lawsuit against the manufacturers of Zicam and Cold-Eeze nasal gels, claiming that they lost their sense of smell after using the product, which was settled in January 2006.
In a $12 million settlement, the company admitted no wrongdoing or admission that their products caused loss of the sense of smell.
This lawsuit spurred a lot of conversation about these products; I have personally received numerous emails from people who say that they, too, have lost their sense of smell after using Zicam.
My ThoughtsThe lack of a large-scale study on these medications is concerning. It is best not to use these products until there is further investigation.
Sources:
McBride K, Slotnick B, Margolis FL. Does intranasal application of zinc sulfate produce anosmia in the mouse? An olfactometric and anatomical study. Chem Senses. 2003 Oct;28(8):659-70.
Mossad, Sherif B. "Upper Respiratory Tract Infections." The Cleveland Clinic Disease Management Project 29 July 2005. 03 Nov 2006.
Slotnick B, Sanguino A, Husband S, Marquino G, Silberberg A. Olfaction and olfactory epithelium in mice treated with zinc gluconate. Laryngoscope. 2007 Apr;117(4):743-9.
"Warnings on Three Zicam Intranasal Zinc Products." FDA Consumer Updates 16 June 09. US Food and Drug Administration. 16 June 09.
