Background: It has long been believed that antibiotics have no role in treating common colds yet they are often prescribed in the belief that they may prevent secondary bacterial infections. Given the increasing concerns about antibiotic resistance it is important to examine the evidence for the benefit of antibiotics for the common cold.
Objectives: To determine:(1) the efficacy of antibiotics, in comparison with placebo, for reducing general symptoms and specific nasopharyngeal symptoms of acute upper respiratory tract infections; (2) if antibiotics have any influence on acute purulent rhinitis; (3) whether antibiotics cause significant adverse outcomes in patients with acute upper respiratory tract infections.
Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005); MEDLINE (January 1966 to March, Week 1, 2005); EMBASE (1980 to December 2004), the Family Medicine Database (1908, volume 1 to 1993, volume 13; this database was discontinued in 1993), and reference lists of articles, and we contacted principal investigators.
Selection criteria: Randomised trials comparing any antibiotic therapy against placebo in people with acute upper respiratory tract infections and with less than seven days of symptoms, or acute purulent rhinitis less than ten days in duration.
Data collection and analysis: Both authors independently assessed trial quality and extracted data.
Main results: All analyses used the fixed-effect model unless otherwise stated. The overall quality of the included trials was variable. People receiving antibiotics did no better in terms of lack of cure or persistence of symptoms than those on placebo (relative risk (RR) 0.89, 95% confidence interval (CI) 0.77 to 1.04), based on a pooled analysis of six trials with a total of 1147 patients. Overall, the relative risk of adverse effects in the antibiotic group was RR 1.8 (95% CI 1.01 to 3.21), using a random-effects model. Adult patients had a significantly greater risk of adverse effects with antibiotics than with placebo (RR 2.62, 95% CI 1.32 to 5.18) (random-effects model) while there was no greater risk in children (RR 0.91, 95% CI 0.51 to 1.63). The pooled relative risk for persisting acute purulent rhinitis with antibiotics compared to placebo was 0.57 (95% CI 0.37 to 0.87) (random-effects model), based on 6 studies with 772 participants.
Authors' conclusions: There is insufficient evidence of benefit to warrant the use of antibiotics for upper respiratory tract infections in children or adults. Antibiotics cause significant adverse effects in adults. The evidence on acute purulent rhinitis and acute clear rhinitis suggests a benefit for antibiotics for these conditions but their routine use is not recommended.