Does intranasal zinc gluconate cause anosmia?

January 01, 0001

Does intranasal zinc gluconate cause anosmia?

The Bradford Hill criteria are widely used to establish causality between an environmental agent and disease. These US authors evaluated the relationship between over-the-counter intranasal zinc gluconate therapy and anosmia. The study included 25 patients who presented to the University of California, San Diego, Nasal Dysfunction Clinic complaining of acute-onset anosmia after intranasal application of homeopathic zinc gluconate gel. They assessed each of the 9 Bradford Hill criteria—strength of association, consistency, specificity, temporality, biological gradient (dose- response), biological plausibility, biological coherence, experimental evidence, using patient data and literature reporting other clinical experiences.

They found: "Clinical, biological, and experimental data support the Bradford Hill criteria to demonstrate that intranasal zinc gluconate therapy causes hyposmia and anosmia."

The authors concluded: "The Bradford Hill criteria represent an important tool for scientifically determining cause between environmental exposure and disease. Increased Food and Drug Administration oversight of homeopathic medications is needed to monitor the safety of these popular remedies."

Both physicians and public should be aware of this side effect of intranasal zinc compounds.

For the full abstract, click here.

Arch Otolaryngol Head Neck Surg 136(7):673-676, July 2010
© 2010 to the American Medical Association
The Bradford Hill Criteria and Zinc-Induced Anosmia-A Causality Analysis. Terence M. Davidson, Wendy M. Smith. Correspondence to Dr. Davidson: [email protected]

Category: R. Respiratory. Keywords: zinc gluconate, intranasal, anosmia, causality, homeopathic medications, Branford Hill criteria, mixed method analysis, journal watch.
Synopsis edited by Dr Linda French, Toledo, Ohio. Posted on Global Family Doctor 10 August 2010

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.