Antihistamines
Antihistamines are reversible H1-receptor antagonists that block histamine activity in the respiratory tract, gastrointestinal (GI) tract, and blood vessels. They may help prevent and treat nasal and ocular itching, rhinorrhea, and sneezing associated with the common cold, but they have not been proven to prevent colds, cure them, or shorten the course. Side effects of antihistamines include drowsiness, nervousness, insomnia, dry mouth, and dizziness. OTC cold and allergy formulas for children contain first- or second-generation antihistamines. There is no FDA-approved dosing of antihistamines for colds; however, dosing for allergic rhinitis is given. The two classes differ mainly in their sedative effects, with first-generation antihistamines causing more sedation.3-6
First-generation antihistamines include chlorpheniramine, diphenhydramine, and brompheniramine. Appropriate dosing of chlorpheniramine in children aged 2 to 6 years is 0.35 mg/kg/day divided every four to six hours, with a maximum daily dose (MDD) of 6 mg. Recommended diphenhydramine dosing in children aged 2 to 6 years is 5 mg/kg/day divided six hours as needed, with an MDD of 300 mg. Diphenhydramine should not be used in neonates owing to possible central nervous system effects. Dosing of brompheniramine in patients aged 2 to 6 years is 1 mg every four to six hours.2 Brompheniramine is not available OTC as a single-active-ingredient product, but it is found in combination with other active ingredients in pediatric cough and cold medications.
Second-generation antihistamines available OTC include cetirizine and loratadine. Appropriate cetirizine dosing in children is as follows: age 6 to 12 months, 2.5 mg/day; age 12 to 23 months, initial dosing 2.5 mg/day (may be increased to 2.5 mg twice/day); age 2 to 5 years, initial dosing 2.5 mg/day (may be increased to 5 mg/day in single or divided doses). The usual dose of loratadine for children aged 2 to 5 years is 5 mg once/day.2
Antihistamines should not be used to sedate children, and manufacturers of certain antihistamine products are making voluntary labeling changes that warn parents not to use the product with the intention of making a child sleepy.1 Parents should avoid using antihistamines in children with glaucoma, breathing disorders, liver disease, or seizure disorders unless directed otherwise by their primary health care provider.3-6
Decongestants
Nasal decongestants are sympathomimetic amines that exert their vasoconstrictive action by affecting sympathetic tone in the nasal mucosa. Decongestants decrease enlarged blood vessels and alleviate mucosal edema by acting on adrenergic receptors.5,7,8 Phenylephrine stimulates alpha-1 receptors, whereas oxymetazoline, xylometazoline, and naphazoline stimulate alpha-2 receptors.8
Pseudoephedrine exerts its action by having both a direct and an indirect effect on adrenergic activity. Like phenylephrine and the imidazoline derivatives, pseudoephedrine stimulates alpha receptors but also indirectly causes the release of norepinephrine from its storage sites.7,8
Systemic and nasal decongestants are available OTC. Systemic nasal decongestants are indicated for temporary relief of nasal congestion, to promote nasal or sinus drainage, and for cough caused by postnasal drip. Topical nasal decongestants are indicated for the symptomatic relief of both nasal and nasopharyngeal mucosal congestion.5,7
Side effects from decongestants are more likely to occur in children than in adults. Effects include elevated blood pressure, tachycardia, palpitations, arrhythmia, restlessness, insomnia, anxiety, tremors, psychological disturbances, and hypersensitivity reactions. Because they are minimally absorbed, topical decongestants have systemic side effects that are milder and occur less frequently compared with systemic dosage forms. Topical use may cause burning, stinging, sneezing, or local irritation. The use of topical decongestants should be limited to three days, since prolonged use has been associated with tachyphylaxis, rebound nasal mucosa edema, and rebound nasal congestion.5,7,8
The recommended dosing for phenylephrine nasal drops is 1 to 2 drops of 0.16% solution in each nostril every three hours as needed in infants older than 6 months; in children aged under 6 years, the dosing is 2 to 3 drops of 0.125% solution in each nostril every four hours as needed.2 Appropriate dosing of oral phenylephrine in children aged 2 to 6 years is 2.5 mg every four hours or 3.75 mg every six hours, with an MDD of 15 mg.2,9 Pseudoephedrine in children aged under 12 years is dosed at 4 mg/kg/day divided every six hours as needed with an MDD of 60 mg.2,9
Expectorants
Guaifenesin is the only nonprescription expectorant available for use in children. It is an oral mucolytic that helps loosen phlegm and bronchial secretions by increasing respiratory-tract secretions, which leads to a more productive cough and better airway clearance.6 If the cough lasts for more than one week, recurs, or is accompanied by a fever, rash, or persistent headache, consultation with a primary health care provider is recommended. Adverse effects associated with guaifenesin include nausea, vomiting, dizziness, drowsiness, headache, and rash.
Guaifenesin should be taken with a full glass of water, and adequate hydration during use should be maintained. The extended-release tablets should not be chewed or crushed; therefore, if the patient cannot swallow the tablet, a different dosage form--such as syrup, solution, liquid, or minimelt (oral granule)--should be used. The most effective way to administer the oral granules is to place them on the tongue and swallow them without chewing; they may have an unpleasant taste if chewed. Appropriate dosing for children aged up to 6 years is as follows: age under 2 years, individualized dose (common dosing = 25-50 mg every four hours, with an MDD of 300 mg); age 2 to 6 years, 50 to 100 mg every four hours, with an MDD of 600 mg.4-6
Antitussives
Codeine, although not available OTC in all states, is the gold-standard antitussive. Nonprescription antitussives that are available OTC to treat cough are dextromethorphan and diphenhydramine.10 Codeine produces cough suppression by acting centrally on the cough center located in the medulla portion of the brainstem. When used at antitussive doses, codeine should not exhibit addictive properties.10 Dextromethorphan, the d-isomer of codeine, exerts its pharmacologic action in the same way as codeine; however, it lacks analgesic and addictive properties when used at recommended doses.4,5 In children, the recommended dose of both dextromethorphan and codeine is 1 mg/kg/day divided into four doses, with an MDD of 30 mg for children aged 2 to 5 years.2,11 Recommended dosing for diphenhydramine, a first-generation antihistamine, in children aged less than 6 years is 5 mg/kg/day divided every six hours, with an MDD of 300 mg.2
Side effects of codeine include lightheadedness, dizziness, sedation, GI effects, and sweating. The most common effects resulting from an overdose are respiratory depression and a decreased level of alertness or consciousness. It has been reported that codeine is unlikely to produce significant side effects in children given less than 2 mg/kg; however, somnolence, ataxia, miosis, vomiting, rash, facial swelling, and itching have been reported in children receiving codeine doses of 3 to 5 mg/kg/day. Side effects of dextromethorphan include drowsiness, dizziness, nausea, GI upset, and abdominal discomfort.4 Dextromethorphan may cause behavioral disturbances and respiratory depression when overdosage occurs.
Insufficient evidence exists to support the use of codeine or dextromethorphan for antitussive purposes in the pediatric population.11 Pharmacists should counsel parents about the lack of data supporting the use of these drugs for antitussive purposes as well as the potential risks associated with their use. Additionally, evidence suggests that second-generation nonsedating antihistamines such as loratadine are ineffective for lessening cough associated with the common cold, and therefore should not be used.12
Combination Products
Many nonprescription cough and cold formulations contain more than one active ingredient to treat two or more simultaneous symptoms. It is important to remember that combination cough and cold medications should be used only if the corresponding symptom is present and that combination products should not be given in addition to a different nonprescription product with the same active ingredient.
Nonprescription cough and cold formulations are available in the following combinations: antihistamine/decongestant, antihistamine/antitussive, antitussive/expectorant, decongestant/expectorant, antihistamine/antitussive/
Voluntary and Regulatory Changes
The safety of OTC cough and cold preparations in the pediatric population is of great concern owing to reports of severe adverse reactions and deaths in infants and children. In October 2007, the FDA's advisory committees on Nonprescription Drugs and Pediatrics met to discuss the safety and efficacy of nonprescription cough and cold medications in children. Ten days prior to the meeting, a voluntary withdrawal of 14 nonprescription infant cough and cold medications was announced by the Consumer Healthcare Products Association (CHPA) on behalf of the products' manufacturers. Manufacturers recalled these products even though they believed that they were safe. Cases of misuse leading to overdose of infants less than 2 years of age had been reported. The advisory committees concluded that evidence from pediatric studies was insufficient to prove the efficacy of cold and cough medications in children; they voted 13 to 9 to recommend that cough and cold products no longer be used in children under 6 years of age.13,14
The FDA issued a public health advisory in January 2008 recommending that OTC cough and cold medications not be used in children under 2 years of age because of the risk of serious, life-threatening adverse events. Additionally, the FDA agreed to the manufacturers' request to change the product labeling to warn parents not to use antihistamine products to sedate children.13,14
In 2008, the FDA held two public meetings to gather more information about the regulatory process for pediatric cough and cold medicines and about scientific testing in children. On October 8, 2008, the FDA issued a statement supporting the CHPA's announcement that manufacturers of nonprescription OTC cough and cold medicines for children were voluntarily modifying package labeling to state, "Do not use in children under 4 years of age."15
In addition to product-labeling changes, new child-resistant packaging and measuring devices for the products are being introduced. The manufacturers have been transitioning this new labeling and packaging throughout the 2008-2009 cough and cold season.1
Complementary and Alternative Therapies
Alternative cough and cold therapies such as increased fluid intake, room humidifiers, nasal dilator strips, nasal aspiration or irrigation, and vitamin C can be used alone or in combination with an OTC cough and cold medication. Increased fluid intake helps prevent dehydration in a child suffering from a cough or cold. Room humidifiers provide relief from congestion by moistening the air.16 Warm-mist humidifiers work by boiling water in a reservoir, thereby posing a potential burn risk; for that reason, cool-mist humidifiers are generally recommended. Because bacteria thrive in moist settings, parents should be encouraged to empty water from the humidifier and wipe all surfaces dry on a daily basis.17
Nasal dilator strips are adhesive bands placed on the nose that dilate the nasal air passages or stiffen the nasal wall, leading to increased airflow and thus relieving nasal congestion.18,19 Nasal dilator strips with or without added menthol are FDA-approved for use in children aged 5 years or older. Latex allergy is a potential concern with this product.18
Cleansing of the nasal passages with a bulb syringe and nasal irrigation with saline drops are two options for treating small children with congestion. Aspiration with a bulb syringe clears mucus from the nasal passages; 0.65% sodium chloride drops and sprays soothe irritated mucus membranes and rehydrate dried secretions for easier removal from the nasal passages.7,18
Supplementation with vitamin C may decrease the duration of the common cold in children. A 2004 Cochrane systematic review suggests that, in children, doses of 0.2 g to 2 g vitamin C are beneficial for reducing a cold's duration. Studies have shown that children have a greater decrease in cold duration than adults, and that higher doses confer a greater benefit than lower doses. Studies evaluating 0.2 to 0.75 g/day vitamin C reported a 7% reduction in cold duration compared with an 18% reduction in studies evaluating 1 g/day.20 Children given 2 g/day demonstrated a median decrease in cold duration of 26%, versus a 6% median decrease in adults receiving 1 g/day.21 At doses greater than 1 g, side effects including nausea, vomiting, increased iron absorption, and diarrhea may occur.5
Conclusion
Pharmacists are accessible members of the health care team and are often consulted by parents or guardians regarding selection of appropriate nonprescription cough and cold products for their children. The parent or guardian should be counseled to carefully follow certain guidelines for usage (see sidebar) when an OTC cough and cold medication is being considered for use in children.22,23
3/18/2009
US Pharm. 2009;34(3):33-35.
