No Proof Over-the-Counter Cough Medicines WorkJan 23, 2008 | Parker Waichman LLP
Cough medicine, known to be a dangerous drug for young children, is not a good choice for adults either. According to a recent analysis of studies done on cough medicines, there is little evidence that these medications do very much to relieve symptoms in children or adults. What’s more, the studies the makers of cough medicine use to back up their claims that such drugs are helpful are often skewed in favor of the cough medicines.
Researchers from Royal College of Surgeons in Ireland Medical School reviewed 25 cough medicine studies, 17 of which involved 2,876 adults and eight of which involved 616 children. In the adult studies, six compared antitussives medicines used to relieve coughs, such as Robitussin, with placebo and had variable results. Two studies compared an expectorant such as Mucinex, which promotes the discharge of mucus from the respiratory tract, with placebo; one found benefits. Another two studies focusing on combinations of antihistamine and decongestants produced conflicting results, while three studies found antihistamines were no more effective than placebo in relieving cough. Three other adult studies compared combinations of drugs with placebo and showed some benefit in reducing cough; one study found that mucolytics, which break down mucus, reduced cough frequency.
In studies involving children, seven -- two with antitussives, two with antihistamines, two with antihistamine decongestants and one with antitussive-bronchodilator combinations -- showed the drugs were no more effective than placebo. (Bronchodilators work to ease coughs by widening air passages.) In another study of two pediatric cough syrups, Triaminicol and Dacol, both showed "satisfactory" response compared to placebo medicines. Based on those results, the researchers were unable to say how well cough medicines in general relieved symptoms.
The review of cough medicine studies also found the outcome of a particular study – favorable or unfavorable to the medications – could often be predicted based on the organization paying for it. According to the researchers, "six out of the nine studies that were supported by the pharmaceutical industry showed positive results compared to three positive studies out of 16 trials that did not report any conflict of interest."
In the past several years, concerns have arisen over the safety of over-the -counter cough and cold medicine, especially in children. Earlier this week, the Food & Drug Administration (FDA) issued a warning that such medicines should not be given to children under two. The FDA is still reviewing these medications for use in older children, and could provide further guidance in the coming months.
Given that there is no proof that they work, some of the researchers questioned the necessity of such cough medicines. People often worry if a cough lasts a few days, but the average duration for a cough is two weeks for adults and three weeks for children. And coughing is not necessarily a bad thing, as it is often an efficient mechanism for clearing viruses from the respirator system. "I do not give my kids over-the-counter cough medicine," said Thomas Fahey, professor of general practice at the Royal College of Surgeons in Ireland Medical School and review co-author. "I do not advise my patients to do so."