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 LETTERS

The problem with zinc lozenges

As the authors of “Do OTC remedies relieve cough in acute URIs?” noted, half of the clinical trials of zinc lozenges for colds in the last 25 years showed benefit and half did not. Worse, clinical response to zinc lozenges has varied from shortening symptoms by 7 days¹ to increasing the duration by 4 to 5 days.²

The enormous difference relates to lozenge formulation.³ Lozenges that release ionic zinc shorten colds and cough in a dose-response manner. Those that don’t release ionic zinc not only do not shorten the duration of symptoms, but may make cough and colds worse.³

I studied the contents of more than 40 zinc lozenges and found that few (or none) release substantial ionic zinc in the sustained manner needed for symptom relief.³ We need a pharmaceutical company to make a zinc lozenge that can shorten cough and colds by a week and take it through the FDA approval process.

George Eby
George Eby Research Institute
Austin, Tex

References

1. Eby GA, Davis DR, Halcomb WW. Reduction in duration of common colds by zinc gluconate lozenges in a double-blind study. Antimicrob Agents Chemother. 1984;25:20–24.
2. Douglas RM, Miles HB, Moore BW, et al. Failure of effervescent zinc acetate lozenges to alter the course of upper respiratory tract infections in Australian adults. Antimicrob Agents Chemother. 1987;31:1263–1265.
3. Eby GA  3rd. Zinc lozenges as cure for the common cold—a review and hypothesis. Med Hypotheses. 2009 November 9 [Epub ahead of print].

The Journal of Family Practice ©2010 Quadrant HealthCom Inc.