Q&A

Zinc nasal gel effective for the common cold

J Fam Pract. 2003 May;52(5):349-364
By
Gloria Rizkallah, PharmD
Terry Seaton, PharmD
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  • BACKGROUND: Although the common cold is self-limiting, adults develop colds approximately 2 to 4 times per year. Zinc may decrease the length and severity of cold symptoms by several possible mechanisms. Studies using other zinc dosage forms, including lozenges, have demonstrated mixed results.
  • POPULATION STUDIED: This study enrolled 49 women and 29 men with mean age of 26 years (range=21–40 years); 2 additional subjects in the control group were lost to follow-up. Study groups were similar at baseline. Subjects had common cold symptoms (2 major and 1 minor or 1 major and 3 minor symptoms ) for more than 24 hours and less than 48 hours.
  • STUDY DESIGN AND VALIDITY: This was a randomized, double-blind trial of a nasal gel containing zinc gluconate administered via a pump, or an identical placebo. One investigator recruited all patients, and allocation was concealed from the enroller. Patients applied 2 sprays 4 times daily (total daily elemental zinc dose, 2.1 mg) until symptoms resolved or for 10 days, whichever came first. Patients were asked to refrain from using other cold remedies, but they could take acetaminophen for fever control if desired.
  • OUTCOMES MEASURED: The primary outcome was time to cold resolution, defined as number of symptomatic days from onset until resolution. Secondary outcomes included self-reported total daily symptom scores and incidence of adverse events. Although not an explicit outcome, the investigator collected and reported viral cultures to identify the viral isolates.
  • RESULTS: Zinc gel reduced the median time to cold resolution more than placebo (4.3 vs 6 days; P=.002) and decreased the median time to resolution of nasal congestion, nasal drainage, and sore throat. Active drug improved total symptom scores but data were not reported. Adverse events did not differ between the 2 groups; nasal stinging or burning were common (12.5% zinc vs 5% placebo). Subjects were unable to correctly guess which treatment they were receiving after 1 day.
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PRACTICE RECOMMENDATIONS

Zinc nasal gel (Zicam) reduced the duration of the common cold by 41 hours, was well tolerated, and was relatively inexpensive.

More studies, in a broader population, comparing zinc nasal gel with other cold remedies (such as decongestants, antihistamines, antitussives, and antipyretics/analgesics) are needed before recommending it as first-line therapy.

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