The efficacy of cough medication is questionable, particularly in children. Some cough medicines may be no more effective than
placebos for acute coughs in adults, including coughs related to upper respiratory tract infections. The
American College of Chest Physicians emphasizes that cough medicines are not designed to treat
whooping cough, a cough that is caused by bacteria and can last for months. No over-the-counter cough medicines have been found to be effective in cases of
pneumonia. They are not recommended in those who have
COPD,
chronic bronchitis, or the
common cold.
Medications •
Dextromethorphan (DXM) may be modestly effective in decreasing cough in adults with viral upper respiratory infections. However, in children, it has not been found to be effective. •
Codeine was once viewed as the "gold standard" in cough suppressants, but this position is now questioned. Some
placebo-controlled trials have found that it is ineffective against some forms of cough, including acute cough in children. Additionally, there is no evidence that
hydrocodone is useful in children. Similarly, a 2012 Dutch guideline does not recommend its use to treat acute cough. • A number of other commercially available cough treatments have not been shown to be effective in viral upper respiratory infections. These include for adults:
antihistamines, antihistamine-decongestant combinations,
benzonatate, anti asthmatic-expectorant-mucolytic combinations, expectorant-bronchodilator combinations, leukotriene inhibitors,
ambroxol, and
guaifenesin, sometimes with analgesics, antipyretics, anti inflammatories, and anticholinergics; and for children: antihistamines,
decongestants for clearing the nose, or combinations of these and leukotriene inhibitors for allergy and asthma. Long term diphenhydramine use is associated with negative outcomes in older people.
Alternative medicine A small study found
honey may be a minimally effective cough treatment due to "well-established antioxidant and antimicrobial effects" and a tendency to soothe irritated tissue. A
Cochrane review found there was weak evidence to recommend for or against the use of honey in children as a cough remedy. In light of these findings, the Cochrane study found honey was better than no treatment, placebo, or diphenhydramine but not better than dextromethorphan for relieving cough symptoms. Many
alternative treatments are used to treat the
common cold, though data on effectiveness is generally limited. A 2007 review states that, "alternative therapies (i.e.,
Echinacea,
vitamin C, and
zinc) are not recommended for treating common cold symptoms; however, Vitamin C prophylaxis may modestly reduce the duration and severity of the common cold in the general population and may reduce the incidence of the illness in persons exposed to physical and environmental stresses." A 2014 review also found insufficient evidence for Echinacea, where no clinical relevance was proven to provide benefit for treating the common cold, despite a weak benefit for positive trends. Similarly, a 2014 systematic review showed that garlic may prevent occurrences of the common cold but there was insufficient evidence of garlic in treating the common cold and studies reported adverse effects of a rash and odour. Therefore, more research needs to be done to prove that the benefits outweigh the harms. Evidence supporting the effectiveness of zinc is mixed with respect to cough. Zinc gel in the nose may lead to long-term or permanent loss of smell. The FDA therefore discourages its use.
Recreational usage Cough medicines, especially those containing
dextromethorphan and
codeine, are often abused as
recreational drugs. ==Adverse effects==