Systematic review of randomised controlled trials of over the counter cough medicines for acute cough in adults.
OBJECTIVE
To determine whether over the counter cough medicines are effective for acute cough in adults.


METHODS
Systematic review of randomised controlled trials.


METHODS
Search of the Cochrane Acute Respiratory Infections Group specialised register, Cochrane Controlled Trials Register, Medline, Embase, and the UK Department of Health National Research Register in all languages.


METHODS
All randomised controlled trials that compared oral over the counter cough preparations with placebo in adults with acute cough due to upper respiratory tract infection in ambulatory settings and that had cough symptoms as an outcome.


RESULTS
15 trials involving 2166 participants met all the inclusion criteria. Antihistamines seemed to be no better than placebo. There was conflicting evidence on the effectiveness of antitussives, expectorants, antihistamine-decongestant combinations, and other drug combinations compared with placebo.


CONCLUSIONS
Over the counter cough medicines for acute cough cannot be recommended because there is no good evidence for their effectiveness. Even when trials had significant results, the effect sizes were small and of doubtful clinical relevance. Because of the small number of trials in each category, the results have to be interpreted cautiously.
Schroeder
Knut
K
Division of Primary Health Care, University of Bristol, Bristol BS6 6JL. k.schroeder@bristol.ac.uk
Fahey
Tom
T
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000996:Antitussive Agents / Q000627:therapeutic use*; D003371:Cough / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D008875:Middle Aged; D004366:Nonprescription Drugs / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000150:complications
D000996:Antitussive Agents; D004366:Nonprescription Drugs