July 20, 2010

Zinc-based Nasal Sprays Can Cause Loss Of Smell

Popular zinc-based nasal gels and sprays sold over-the-counter as common cold remedies are ineffective, and can even cause the loss of smell, according to a study published Monday.

Clinical trials of the zinc-based therapies showed they did not prevent or reduce the duration of common colds, and were linked to a loss of smell, the study's authors found.

"In addition to concerns regarding the efficacy of intranasal zinc therapy, increasing evidence indicates that this medication may be linked to severe, potentially permanent hyposmia (reduced sense of smell) and anosmia (loss of smell)," the authors wrote in a report about their study.

The scientists conducted a clinical trial with 25 people using the zinc-based remedies, and also analyzed reports of biological, clinical and experimental data.

Only one of the studies analyzed showed a reduction in cold severity due to the zinc remedies.  However, that study was funded by the maker of the zinc-based medicine involved in the trial.

Given their findings, the scientists called on the U.S. Food and Drug Administration (FDA) to boost regulations of zinc-based cold remedies and other homeopathic zinc-based therapies. 

"Only homeopathic drugs offered for treatment of 'serious disease conditions' must be dispensed by a licensed practitioner," the authors said.

Homeopathic products that treat less serious conditions, such as the common cold, are sometimes sold over-the-counter. As such, they are not subject to "the rigorous pre-market approval process that allopathic medications must go through before entering the market," the authors wrote.

The study was published Monday in the Archives of Otolaryngology, a journal of the American Medical Association. 


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