Duration of Symptoms and Plasma Cytokine Levels in Patients with the Common Cold Treated with Zinc Acetate

A Randomized, Double-Blind, Placebo-Controlled Trial

15 August 2000 | Volume 133 Issue 4 | Pages 245-252

Background: Adults and children in the United States get two to six colds per year. Evidence that zinc is effective therapy for colds is inconsistent.

Objective: To test the efficacy of zinc acetate lozenges in reducing the duration of symptoms of the common cold.

Design: Randomized, double-blind, placebo-controlled trial.

Setting: Detroit Medical Center, Detroit, Michigan.

Patients: 50 ambulatory volunteers recruited within 24 hours of developing symptoms of the common cold.

Intervention: Participants took one lozenge containing 12.8 mg of zinc acetate or placebo every 2 to 3 hours while awake as long as they had cold symptoms.

Measurements: Subjective symptom scores for sore throat, nasal discharge, nasal congestion, sneezing, cough, scratchy throat, hoarseness, muscle ache, fever, and headache were recorded daily for 12 days. Plasma zinc and proinflammatory cytokine levels were measured on day 1 and after participants were well.

Results: Forty-eight participants completed the study (25 in the zinc group and 23 in the placebo group). Compared with the placebo group, the zinc group had shorter mean overall duration of cold symptoms (4.5 vs. 8.1 days), cough (3.1 [95% CI, 2.1 to 4.1] vs. 6.3 [CI, 4.9 to 7.7] days), and nasal discharge (4.1 [CI, 3.3 to 4.9] vs. 5.8 [CI, 4.3 to 7.3] days) and decreased total severity scores for all symptoms (P < 0.002, test for treatment x time interaction). Mean changes in soluble interleukin-1 receptor antagonist level differed nonsignificantly between the zinc group and the placebo group (difference between changes, –89.4 pg/mL [CI, –243.6 to –64.8 pg/mL]).

Conclusion: Administration of zinc lozenges was associated with reduced duration and severity of cold symptoms, especially cough. Improvement in clinical symptoms with zinc treatment may be related to a decrease in proinflammatory cytokine levels; however, in this study, the observed differences between changes in cytokine levels in zinc and placebo recipients were not significant.

Author and Article Information

From Wayne State University School of Medicine, Detroit, Michigan; and University of Michigan Medical School, Ann Arbor, Michigan.

Acknowledgments: The authors thank Diane Snell, Karen Mirisola, James Nowak, and Sally Bates for technical and secretarial assistance.

Grant Support: In part by an unrestricted fund from the George and Patsy Eby Research Foundation.

Requests for Single Reprints: Ananda S. Prasad, MD, PhD, Department of Medicine, Division of Hematology-Oncology, Wayne State University, University Health Center 5-C, 4201 St. Antoine, Detroit, MI 48201.

Requests To Purchase Bulk Reprints (minimum, 100 copies): the Reprints Coordinator; phone, 215-351-2657; e-mail, reprints{at}mail.acponline.org.

Current Author Addresses: Drs. Prasad, Bao, and Beck: Department of Medicine, Division of Hematology-Oncology, Wayne State University, University Health Center, 5-C, 4201 St. Antoine, Detroit, MI 48201.

Dr. Fitzgerald: Department of Medical Education, University of Michigan, G-1100 Towsley Center 0201, Ann Arbor, MI 40109-0201.

Dr. Chandrasekar: Division of Infectious Diseases, Department of Medicine, Wayne State University, Harper Hospital, 4-Yellow Center, 3990 John R., Detroit, MI 48201.

Author Contributions: Conception and design: A.S. Prasad, P.H. Chandrasekar.

Analysis and interpretation of the data: A.S. Prasad, J.T. Fitzgerald, B. Bao, F.W.J. Beck.

Drafting of the article: A.S. Prasad, J.T. Fitzgerald.

Critical revision of the article for important intellectual content: A.S. Prasad.

Final approval of the article: A.S. Prasad, P.H. Chandrasekar.

Provision of study materials or patients: A.S. Prasad, P.H. Chandrasekar.

Statistical expertise: J.T. Fitzgerald.

Obtaining of funding: A.S. Prasad.

Administrative, technical, or logistic support: A.S. Prasad, F.W.J. Beck.

Collection and assembly of data: J.T. Fitzgerald, B. Bao, F.W.J. Beck.