Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate. A randomized, double-blind, placebo-controlled trial.
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.


METHODS
Randomized, double-blind, placebo-controlled trial.


METHODS
Detroit Medical Center, Detroit, Michigan.


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


METHODS
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.


METHODS
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]).


CONCLUSIONS
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.
Prasad
A S
AS
Department of Medicine, Wayne State University, University Health Center, Detroit, Michigan 48201, USA.
Fitzgerald
J T
JT
Bao
B
B
Beck
F W
FW
Chandrasekar
P H
PH
D000328:Adult; D003139:Common Cold / Q000097:blood* / Q000150:complications / Q000188:drug therapy*; D003371:Cough / Q000188:drug therapy / Q000209:etiology; D016207:Cytokines / Q000097:blood*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D009297:Nasal Mucosa / Q000378:metabolism; D019798:Neopterin / Q000097:blood; D010919:Placebos; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors / Q000097:blood; D018124:Receptors, Tumor Necrosis Factor / Q000097:blood; D012107:Research Design / Q000592:standards; D016896:Treatment Outcome; D019345:Zinc Acetate / Q000009:adverse effects / Q000627:therapeutic use*
D016207:Cytokines; D010919:Placebos; D017472:Receptors, Interleukin-1; D018124:Receptors, Tumor Necrosis Factor; D019798:Neopterin; D019345:Zinc Acetate