Are over-the-counter (OTC) cough medications safe and effective in reducing acute cough symptoms in children and adults?
It is uncertain whether OTC cough medications are effective in reducing cough symptoms in adults; in children, no trials show a statistically significant benefit in the treatment compared with the placebo groups. Overall, the quality of evidence is poor; adult studies show conflicting results from heterogeneous studies. Evidence from trials about adverse effects is limited; however, national databases have reported ingestion-related harms in children.
The authors of this Cochrane review found 17 trials in adults and eight trials in children. The 17 adult trials (n = 2,876) compared antitussives, antihistamines, expectorants, or combinations with placebo and measured self-reported and objective cough symptoms.
Two out of three adult studies of dextromethorphan, including one meta-analysis of five studies, found a statistically significant benefit: a 30-mg single dose was more effective than placebo in reducing cough symptoms, as measured by cough counts, frequency, effort, and intensity.
Based on the findings of two adult trials of codeine (n = 163) and three trials of antihistamines (n = 1,900), neither medication is more effective than placebo in reducing cough symptoms. Two adult trials (n = 356) comparing antihistamine-decongestant combinations with placebo showed conflicting results, with only the smaller of the two studies showing a statistically significant reduction in mean cough severity rating (mean severity rating 1.4 versus 2.0 out of 4 on days three to five [ P < .05]).
Two adult trials compared guaifenesin with placebo with mixed results: in the larger study (n = 239), a greater percentage of patients in the guaifenesin group than in the placebo group reported reduction of cough frequency and intensity at 72 hours (75 versus 31 percent [ P < 0.01]). The second study (n = 65) found no statistically significant reduction in cough frequency and intensity in the treatment group, but did show more participants reporting a reduction in sputum thickness in the treatment group compared with placebo (96 versus 54 percent [ P = .001]).
In children, all treatment trials of medications available in the United States showed no statistically significant difference in cough-related benefits in the treatment group compared with placebo. Three studies of dextromethorphan, one trial of pediatric cough syrup combinations (dextromethorphan, guaifenesin, and pseudoephedrine; and dextromethorphan, guaifenesin, and pseudoephedrine), and two trials of antihistamine-decongestant combinations showed that these treatments are no more effective than placebo in reducing daytime or nocturnal cough symptoms in children.
Likewise, combination dextromethorphan and albuterol is no more effective than placebo in parent-reported symptom scores. Two trials (n = 243) comparing antihistamines with placebo showed no statistically significant difference in cough symptoms or in parent and child sleep.
Many studies did not report adverse events. Adverse effects reported for adults taking decongestant-antihistamine medications included dry mouth, headache, insomnia, and dizziness. Antihistamine in adults reported adverse effects, including drowsiness, giddiness, and headache. In children, decongestant-antihistamine combination adverse effects included reported hyper-activity and sleepiness.
The U.S. Food and Drug Administration (FDA), in January 2008, strongly advised against the use of OTC cough and cold medications in children younger than two years because of the risk of life-threatening side effects.1 A 2008 Centers for Disease Control and Prevention report estimated that in a two-year period (January 2004 to December 2005), about 7,000 children (younger than 12 years) were treated in emergency departments for adverse drug events attributable to cough and cold medications.2
The American Academy of Pediatrics (AAP) supports the 2008 FDA recommendation against the use of OTC cough and cold medications in those younger than two years. In their last published statement, the AAP concluded that parents should be educated about the lack of proven antitussive effects and the potential risks of these medications in children.3
The American College of Chest Physicians 2006 practice guideline on the evaluation and treatment of cough recommends treating adults who have acute cough caused by the common cold with a first-generation antihistamine-decongestant combination, such as dex-brompheniramine and sustained-release pseudoephed-rine (Drixoral Cold and Allergy 6 mg/120 mg 12-hour tablet). It also endorses the use of naproxen (Naprosyn) in this circumstance.4