Placebo ‘as good as cough syrups’

Many over-the-counter cough medicines are only partly effective, researchers at the Royal College of Surgeons in Ireland have found.

There was “no substantial evidence” that the medicines were effective at treating short-term coughs in adults and children, they reported.

A short-term cough is a common symptom in children and adults suffering from an upper respiratory tract infection caused by a cold.

The researchers examined data from 29 trials involving 4,835 adults and children with a short-term or acute cough (one lasting less than three weeks) to evaluate the effectiveness of the medicines used at different dosages.

The trials of adult medication that compared antitussives, the expectorant guaifenesing, antihistamines and anthistamine-decongestant combinations with a placebo showed either no benefit or variable results.

Most of the child studies that included antitussives, anthistamines, anthistamine-decongestants, and antitussive/bronchodilator combinations found that the medications were no more effective than a placebo.

There was no solid evidence for or against the effectiveness of the medicines used to treat an acute cough.

A limited number of trials showed there was some benefit from treating a cough with mucolytic — a drug used to loosen and clear mucous from the airways.

In one children’s trial, natural honey was found to be more effective than a placebo over a three-day period.

There were 19 studies that found infrequent adverse effects of the medications, mainly minor side-effects such as nausea, vomiting, headache and drowsiness.

Chief author of the study published in The Cochrane Library, Susan Smith, said simple remedies, such as honey and lemon, could provide effective and cheaper relief for a cough.

However she cautioned against giving honey to children under one and recommended that patients talk to their pharmacist or GP for advice on low-cost, safe treatments for coughs that can be prepared at home.

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