Systematic review of randomised controlled trials of over the counter cough medicines for acute cough in adults

doi:10.1136/bmj.324.7333.329

BMJ 2002;324:329 ( 9 February )

Primary care

Systematic review of randomised controlled trials of over the counter cough medicines for acute cough in adults

Knut Schroeder, MRC training fellow in health services research, Tom Fahey, senior lecturer in general practice.

Division of Primary Health Care, University of Bristol, Bristol BS6 6JL

Correspondence to: K Schroeder k.schroeder{at}bristol.ac.uk

Objectives: To determine whether over the counter coughmedicines are effective for acute cough inadults.
Design: Systematic review of randomised controlledtrials.
Data sources: Search of the Cochrane Acute Respiratory InfectionsGroup specialised register, Cochrane Controlled Trials Register,Medline, Embase, and the UK Department of Health National ResearchRegister in alllanguages.
Included studies: All randomised controlled trials that comparedoral over the counter cough preparations with placebo in adultswith acute cough due to upper respiratory tract infection in ambulatorysettings and that had cough symptoms as anoutcome.
Results: 15 trials involving 2166 participants metall the inclusion criteria. Antihistamines seemed to be no betterthan placebo. There was conflicting evidence on the effectivenessof antitussives, expectorants, antihistamine-decongestant combinations,and other drug combinations compared withplacebo.
Conclusion: Over the counter cough medicines for acutecough cannot be recommended because there is no good evidencefor 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 resultshave to be interpretedcautiously.

What is already know on this topic
The NHS encourages self treatment of acute self limiting illnesses

Over the counter cough medicines are commonly used as first line treatment for acute cough

What this study adds
There is little evidence for or against the effectiveness of over the counter cough medicines

Although cough medicines are generally well tolerated, they may be an unnecessary expense

Recommendation of over the counter cough medicines to patients is not justified by current evidence

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Rapid Responses:

Read all Rapid Responses

huge industry: Dr.B.C. Rao
bmj.com, 11 Feb 2002 [Full text]
Ingredient List Too Broad for Fair Assessment of Cough Medicines: Jeff G Taylor
bmj.com, 11 Feb 2002 [Full text]
The gap between practice and research: Kath Checkland
bmj.com, 11 Feb 2002 [Full text]
The self-medication of cough: Merja K. K. Aaltonen, et al.
bmj.com, 12 Feb 2002 [Full text]
Re: The gap between practice and research: Paul C Emerson
bmj.com, 13 Feb 2002 [Full text]
Placebo formulations of cough medicines.: Hilary Davies
bmj.com, 14 Feb 2002 [Full text]
Constituents of over the counter cough medicines: Philip J Rogers
bmj.com, 18 Feb 2002 [Full text]
The Cough Medicines Topic.: Celine M Aranjo
bmj.com, 18 Feb 2002 [Full text]
Review should not change existing UK guidance on cough medicines: James Walmsley, et al.
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Re: Re: The gap between practice and research: Kath Checkland
bmj.com, 27 Feb 2002 [Full text]
Over-the-counter cough remedies: John Widdicombe, et al.
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Re: Over-the-counter cough remedies: Lucy A Pavesi, et al.
bmj.com, 5 Mar 2002 [Full text]
NHS Direct does not advocate cough medicines: Mike Sadler
bmj.com, 23 Apr 2002 [Full text]
Established Benefit of Dextromethorphan in Cough: R. William Soller, Ph.D.
bmj.com, 6 Jun 2002 [Full text]
Non-Toxic Cough Treatment That Works: Sharon J Williams
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