Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn

RCSI study finds many over the counter cough medicines have limited effectiveness in treating coughs

29 January 2015

A study carried out by researchers at RCSI (Royal College of Surgeons in Ireland) has found that there is no substantial evidence that over-the-counter medicines are effective in treating short-term coughs in children and adults. The research which was carried out by the Health Research Board (HRB) Centre for Primary Care Research, Department of General Practice, RCSI has been published in The Cochrane Library.

A short term (acute) cough is a common and troublesome symptom in children and adults suffering from upper respiratory tract infection (URTI) caused by a cold. Many people self-prescribe over-the-counter (OTC) cough preparations, and health practitioners often recommend their use for the initial treatment of cough.

Data from 29 trials involving 4835 adults and children with acute coughs was examined to determine the effectiveness of various types of over-the-counter (OTC) medications used at different dosages when compared with a placebo. The majority of the trials of adult medications, (which compared antitussives, the expectorant guaifenesin, antihistamines and antihistamine-decongestant combinations with placebo) showed either no benefit or variable results. The majority of the child studies (which included antitussives, antihistamines, antihistamine-decongestants and antitussive/bronchodilator combinations) found that the medications were no more effective than placebo. A limited number of trials showed benefits including a trial in both children and adults which favoured active treatment with mucolytics over placebo and a trial in children indicated that natural honey was more effective than placebo over a three-day period.

The research found no solid evidence for or against the effectiveness of OTC medications in acute cough. Furthermore, 19 studies reported infrequent adverse effects of these medications which were mainly minor side effects such as nausea, vomiting, headache and drowsiness.

Lead author on the study Professor Susan Smith, Associate Professor, HRB Centre for Primary Care Research in the RCSI Department of General Practice said: "There is a high prevalence of coughs and colds at this time of year and patients often buy over the counter medications to alleviate their symptoms. However, our study has found little evidence to support expenditure on these over the counter medications for coughs and some of these medicines can occasionally result in adverse side-effects. Simple remedies such as honey and lemon can provide effective relief for coughs at a lower cost than over-the-counter medicines. However, parents should note that honey should not be given to children under the age of one. We recommend that patients talk to their pharmacist or GP for advice on low-cost safe treatments for coughs that can be prepared at home."

Graham Love, Chief Executive at the Health Research Board added: "Research like this helps people and doctors to make sound, evidence-based decisions about healthcare choices."

Professor Smith's co-authors on the study are Dr Knut Schroeder Academic Unit of Primary Health Care, Department of Community Based Medicine at the University of Bristol, UK and colleague Professor Tom Fahey, Professor of General Practice, HRB Centre for Primary Care Research, Department of General Practice, RCSI.

RCSI is a not-for-profit health sciences organisation that focuses on education and research to drive positive change in all areas of human health, worldwide. RCSI is headquartered in Dublin and is a recognised College of the National University of Ireland. In 2010, RCSI was granted independent degree-awarding status by the State, which enables the College to award degrees alongside its traditional powers to award licentiates.

The Health Research Board (HRB) is Ireland's lead agency supporting and funding health research. It aims to improve people's health, patient care and health service delivery by leading and supporting research, generating new knowledge and promoting the use of evidence in policy and practice. To date, the HRB has supported a wide range of research which has played a key role in driving innovation in the Irish health system and supporting economic development.