Nasal zinc sprays can impair sense of smell--study

A team of researchers from the University of California, San Diego, and the Veterans Affairs San Diego Health System initiated the present analysis that investigated the effectiveness of the nasal sprays in fighting cold and linked it with loss of sense of smell.

“Increased Food and Drug Administration oversight of homeopathic medications is needed to monitor the safety of these popular remedies," Dr Terence M Davidson and Dr Wendy Smith, co-authors of the research inform.

They noted that while the FDA prescribed that only under ‘serious disease condition’ the drug should be supplied, still there were no regulations on the illegal sale of the nasal spray, without the doctor’s prescription.

Researchers point to the fact that most past studies have also questioned the effectiveness of the zinc gluconate nasal sprays, but they continue to top the sales as a major cold-preventing remedy.

Details of the study
The researchers carried out the analysis on 25 individuals who had suffered a loss of sense of smell after using the zinc gluconate gel and had been examined at the Nasal Dysfunction Clinic of the University of California.

Past medical evidences on the connection between olfactory disorders and use of zinc-based sprays were also taken into account while arriving at the conclusions of the latest study.

The Bradford Hill Criteria, which was developed in 1965 and utilizes a bundle of nine requirements, was used by the researchers to check whether the loss of sense of smell was caused by the zinc nasal spray.

All the nine criteria were satisfied by the link between olfactory problem and use of zinc, as within sometime of using the spray, people reported losing their sense of smell.

“Based on our analysis, it appears evident that intra-nasal zinc can and does cause anosmia,” says Dr Terence M Davidson, lead author of the present study.

"Protecting our patients from the potential risks of intra-nasal zinc medications and other homeopathic drugs, especially ones with limited therapeutic benefit, should be a high priority of the FDA," concluded the study authors.

While the researchers warn against the use of nasal sprays, as their ineffectiveness in preventing colds has been proved in past and present studies, they maintain that these sprays can also cause permanent anosmia, the medical term for loss of sense of smell.

The present study and its findings have been detailed in the July issue of the Archives of Otolaryngology-Head & Neck Surgery.