Department

Pharmacology continuing education

Pharmacology of Cough and Cold Medicines

Decongestants

The decongestants found in children’s OTC cold medication are either pseudoephedrine or phenylephrine. Systemic decongestants are adrenergic receptor agonists (sympathomimetics) that produce vasoconstriction within the mucosa of the respiratory tract, temporarily reducing the swelling associated with inflammation of the mucous membranes. Sympathomimetic drugs work on the α receptors in the vascular smooth muscle causing vasoconstriction and pressor effects and on the β-adrenergic receptors in

Cough Suppressants

Dextromethorphan is the cough suppressant found in OTC cough medications, and it often is combined with the expectorant guaifenesin. Dextromethorphan, the D isomer of the codeine analogue levorphanol, acts centrally in the cough center in the medulla to suppress cough. Drowsiness, dizziness, nausea, and gastrointestinal upset also may be seen with dextromethorphan use.

Diphenhydramine, an antihistamine, also is marketed as a cough suppressant for children (PediaCare Children’s Long-Acting

Expectorants

Guaifenesin is the most commonly prescribed oral mucolytic agent as an expectorant in the United States. Its mechanism of action is to reduce the surface tension and viscosity of the mucus, which increases the ease of expectoration. Respiratory mucus removal is facilitated by increased flow of the thinned secretions via ciliary action. Studies on the efficacy of guaifenesin have failed to demonstrate either improved pulmonary function or decreased sputum viscosity. Hence, its clinical

Antihistamines

Diphenhydramine, chlorpheniramine, and brompheniramine are the antihistamines found in children’s cold and allergy formulas. Antihistamines, also known as H₁ receptor antagonists, compete for and block the action of histamine at the H₁ receptor site on cells in the respiratory tract, gastrointestinal tract, and blood vessels. In the respiratory tract, antihistamines decrease congestion related to allergies.

Naclerio and colleagues (1988) studied the response of inflammatory mediators to induced

Antipyretics

Some multi-symptom cold formulas contain acetaminophen or ibuprofen as an antipyretic and analgesic. Acetaminophen acts centrally to inhibit the synthesis prostaglandins in the CNS and peripherally to block pain impulse generation. Antipyretic activity is due to its action against prostaglandin E₂ in the CNS, which increases in fever (Aronoff & Neilson, 2001). Ibuprofen is a cyclo-oxygenase (COX) enzyme inhibitor. COX is needed for prostaglandin synthesis, and inhibiting COX leads to

Lack of Evidence for Effectiveness of Cough and Cold Medications in Children

Evidence is lacking for the effectiveness of cough and cold medications in children. A recent Cochrane review of the use of decongestants to treat nasal congestion associated with the common cold found a small (6%) but statistically significant improvement in congestion in adults (Taverner & Latte, 2007). The review found insufficient evidence in the literature regarding the effectiveness of decongestants to treat the common cold in children and recommended that decongestants not be used in

Safety of OTC Cough and Cold Medications in Infants and Children

Concerns regarding the safety of cough and cold medications can be found in the scientific literature for at least 15 years. Case reports of infants presenting to the emergency department with OTC cold medication toxicity appear in Pediatrics as early as 1992, with the authors noting that in 1990, 1 in 15 calls to the Maryland Poison Center were regarding cough and cold medications (Gadomski & Horton, 1992). During 2004 and 2005, an estimated 1519 children younger than 2 years were treated in

Recommendations for Use of Cough and Cold Medications

Pediatric nurse practitioners (PNPs) need to be familiar with the safety and efficacy of cold medications in children, including appropriate dosing for different aged children. Parents need to be educated regarding the appropriate use of cough and cold medications in children. Establishing a culture of safety around the use of OTC cough and cold medications will encourage appropriate use and decrease the likelihood of accidental overdose.

Summary

It is clear from the literature that the use of cough and cold medications in infants and young children is not recommended. Evidence is lacking for effectiveness in the treatment of cough and congestion due to the common cold, with real concerns for the safety of using these medications in children younger than 2 years. PNPs should review their practice regarding recommending OTC cough and cold medications to determine if their practice aligns with the standard of practice set by the AAP. PNPs