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allergies or NOT?
Topical Nasal Decongestants • Ephedrine (0.5%) • Levmetamfetamine (0.04-0.15 mg/800 mL of air) • Naphazoline (0.025-0.05%) • Oxymetazoline (0.025-0.05%) • Phenylephrine (0.125-1.0%) • Propylhexedrine (0.4-0.5 mg/800 mL of air • Xylometazoline (0.05-0.1%) Adverse effects associated with decongestants include car- diovascular stimulation (high blood pressure, tachycardia, palpitations, or arrhythmias) and CNS stimulation (restlessness, insomnia, anxiety, tremors, fear, or hallucinations). Children and older adults are more likely than persons in other age groups to experience the associated side effects. Additionally, sys- temic decongestants are more likely to cause adverse effects than topical dosage forms because topical agents are minimally absorbed in the body. However, accidental ingestion of nasal or ocular decongestants can cause adverse effects ranging from nausea, vomiting, and drooling to more serious effects includ- ing hypotension, hyperthermia, lethargy, sedation, and coma. Due to topical decongestants being minimally absorbed, more common side effects related to these agents include propel- lant- or vehicle-associated effects (burning, stinging, sneezing, or local dryness). Rhinitis medicamentosa (RM), also known as rebound congestion, has been associated with the use of topical decongestants. The exact cause of RM is unknown, but short-acting products, preservative agents (benzalkonium chloride), and a long duration of therapy are likely contributing factors. In order to avoid RM, therapy of 3-7 days is the accepted duration for topical decongestants. Due to the associated side effects of decongestants, they have the potential to exacerbate diseases sensitive to adrenergic stimulation, such as hyperten- sion, coronary heart disease, ischemic heart disease, diabetes mellitus, hyperthyroidism, elevated intraocular pressure, and prostatic hypertrophy. Patients that fall in these medical sub- groups should use decongestants only with medical advice. ANTIHISTAMINES Monotherapy with nonprescription antihistamines may provide benefits in adults if started early in the course of a cold (day 1 or 2 of symptom onset). These agents work by blocking histamine within the body, in this case the nose, which causes an itchy nose and swelling. Histamine is released during infectious pro- cesses as a host defense mechanism. Antihistamine efficacy in relieving cold symptoms is conflicting, although many patients seek these medications when suffering from the common cold. Apart from questions of efficacy, an important issue is whether the potential benefits of sedating antihistamines outweigh the known risks associated with these drugs. More information about antihistamines will be discussed in the allergic rhinitis section. LOCAL ANESTHETICS A variety of products containing local anesthetics are avail- able for temporary relief of sore throats. These products may be used every 2-4 hours. A thorough history of a patient’s allergies is warranted before using these agents due to many patients reporting allergic reactions to anesthetics and
should not be used if allergic to benzocaine. Besides aller- gic reactions, benzocaine has also been associated with methemoglobinemia, especially in children younger than 2 years, and should be avoided in this age group. Some products contain local antiseptics (cetylpyridinium chloride, hexylresorcinol) and/or menthol or camphor. Local antiseptics are not effective for viral infections. Emerging evidence sug- gests that menthol and camphor may provide pain relief by stimulation of the TRPM8 or “menthol” receptor. Below are common local anesthetics used for sore throat cold symptoms: • Benzocaine • Pectin • Dyclonine HCl
• Menthol • Phenol
SYSTEMIC ANALGESICS Systemic analgesics, such as acetaminophen, ibuprofen, naproxen, and aspirin, are effective for aches and fever sometimes associated with colds. There has been concern that the use of aspirin and acetaminophen may increase viral shedding and prolong illness but has not been vali- dated. Because of the risk of Reye’s syndrome, aspirin and aspirin-containing products should not be used in children or teenagers who have or are recovering from chickenpox or influenza-like symptoms. Non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, and aspirin) should be used with extreme caution in patients with cardiovascular disease and GI disorders. ANTITUSSIVES AND PROTUSSIVES (EXPECTORANTS) When present, cough associated with colds is usually nonpro- ductive. Antitussive agents (codeine and dextromethorphan) have questionable efficacy in colds, and their use in this setting is not recommended. Guaifenesin is an expectorant and has not been proved effective in natural colds due to its lack of efficacy.
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