Cold medicines are a group of medications taken individually or in combination as a treatment for the symptoms of the common cold and similar conditions of the upper respiratory tract. The term encompasses a broad array of drugs, including analgesics, antihistamines and decongestants, among many others. It also includes drugs which are marketed as cough suppressants or antitussives, but their effectiveness in reducing cough symptoms is unclear or minimal. While they have been used by 10% of American children in any given week, they are not recommended in Canada or the United States in children six years or younger because of lack of evidence showing effect and concerns of harm.
Types There are a number of different cough and cold medications, which may be used for various coughing symptoms. The commercially available products may include various combinations of any one or more of the following types of substances:
Mucokinetics, or mucolytics, are a class of drugs which aid in the clearance of mucus from the airways, lungs, bronchi, and trachea. Examples are carbocisteine, ambroxol, and bromhexine. Expectorants are substances claimed to make coughing easier by modifying the production of mucus. Two examples are acetylcysteine and guaifenesin. Antitussives, or cough suppressants, are substances which suppress the coughing itself. Examples are dextromethorphan, benzonatate, codeine, hydrocodone, pholcodine, noscapine, cloperastine, and butamirate. Antihistamines, for allergic rhinitis, may produce mild sedation and reduce other associated symptoms, like a runny nose and watery eyes. Examples are diphenhydramine, chlorpheniramine, brompheniramine, loratadine, and cetirizine. Decongestants may improve nasal congestion in sinus infections. Examples are ephedrine, phenylephrine, pseudoephedrine, and oxymetazoline. Fever or pain medication. Examples are paracetamol (acetaminophen) and NSAIDs such as ibuprofen or naproxen. Also employed are various substances supposed to soften the coughing, like honey or supplement syrup. An example combination is guaifenesin with codeine.
Effectiveness The efficacy of cough medication is questionable, particularly in children. A 2014 Cochrane review concluded that "There is no good evidence for or against the effectiveness of OTC [over the counter] medicines in acute cough". 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. There is not enough evidence to make recommendations for those who have a cough in cancer.
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. It is thus not recommended for 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. However, antihistamines cannot be used as an empirical therapy in case of chronic, or non-specific cough, especially in very young children. 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. Honey's use as a cough treatment has been linked on several occasions to infantile botulism and accordingly should not be used in children less than one year old. 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. A 2003 review concluded: "Clinical trial data support the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onset of common cold symptoms." Zinc gel in the nose may lead to long-term or permanent loss of smell. The FDA therefore discourages its use.
Recreational usage
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