Close treatment gaps with these common OTCs for respiratory symptoms

Abstract

Medications for treating respiratory symptoms constitute an abundant class of OTC agents and are among the most commonly used OTC meds by children and adults. Conversely, as described in a recent review,1Allergy Asthma Proc. 2018; 39: 169-176Crossref PubMed Scopus (9) Google Scholar consumers and health professionals often lack awareness of data on the efficacy of these products. This in turn can create treatment gaps, in which patients do not receive the most appropriate care. Pharmacists can help patients achieve better relief of respiratory ailments, reduce medication redundancies, and dispel confusion about these commonly used drugs. Antihistamines comprise the largest group of OTC respiratory agents and are the best studied. Through competitive antagonism of histamine (H1), they reduce sneezing, rhinorrhea, and conjunctivitis from inhalant allergens. Antihistamines might disappoint patients with viral-induced symptoms, as they have not been found clinically useful in this regard. Although the anticholinergic effects of a couple are regarded as useful for drying nasal secretions, data on cetirizine, fexofenadine, and chlorpheniramine have shown no such evidence of this outcome. Cetirizine or levocetirizine are used once daily and are most likely to be effective for common problems, such as allergic rhinitis and chronic urticaria. Chlorpheniramine and diphenhydramine are first-generation antihistamines and have noteworthy sedative properties. Diphenhydramine is commonly used as a mild hypnotic to induce sleep. Fexofenadine may be useful for patients experiencing excessive drowsiness from antihistamines, as it has no adverse effects on the central nervous system (CNS), even at higher dosages. Avoid using topical decongestants in patients with chronic rhinitis, as persistent use carries substantial risk of rhinitis medicamentosa, or rebound congestion. These can work well for short-term treatment of nasal congestion resulting from brief viral respiratory infections. I.N. corticosteroids are preferred for maintenance of persistent nasal congestion from allergic rhinitis but provide no benefit for cold symptoms. They effectively decrease nasal inflammation, increasing airflow and decreasing the release of mediators that cause sneezing, itching, and rhinorrhea. Nasal corticosteroid sprays have delayed onsets of maximal effect, so oxymetazoline, a rapid-acting α-1 antagonist, may be useful initially. This agent will rapidly shrink severely swollen mucous membranes and allow for effective delivery of topical corticosteroids. Keep in mind that use of oxymetazoline should be limited to no more than 3 consecutive days because of the risk of rebound congestion. Oral pseudoephedrine has shown moderate effects, but phenylephrine is less poorly absorbed orally because it is inactivated in the gut and during first-pass through the liver. Even after multiple daily doses of four times the FDA-approved OTC dose of phenylephrine, no clinical decongestant effect was observed. While a short course of pseudoephedrine will not raise well-controlled blood pressure higher than 1 mm Hg, it can cause CNS stimulation with associated insomnia and urinary retention in males with benign prostatic hypertrophy. Also known as expectorants, mucolytics are claimed to loosen and clear mucus from airways by increasing its volume and decreasing viscosity. Guaifenesin is marketed as a mucolytic in various products, but in the FDA-approved OTC dose, it neither thins sputum nor decreases volume. Compared with placebo, dextromethorphan, a common OTC cough suppressant, proved slightly better in children aged 2 to 18 years at approved doses, but honey actually provided slightly more benefit. Because of the risk of CNS toxicity, especially in poor metabolizers of the CYP4502D6 enzyme, it is unlikely that antitussive effects will be studied using higher doses of dextromethorphan. I.N. cromolyn, available OTC for seasonal allergic rhinitis, prevents release of mediators like H1 for relief of nasal symptoms. Aside from being less effective than I.N. corticosteroids, it requires administration three to four times daily. Nasal allergy often presents along with red, watery, itchy eyes. While oral antihistamines and nasal corticosteroids may provide some benefit for allergic conjunctivitis, they may not be sufficient for seasons or environments with high allergenic exposure. Eyedrops containing an α-1 adrenergic agonist vasoconstrictor, with or without pheniramine, are available OTC and will provide rapid relief of red eye. Ketotifen, an antihistamine with mast cell stabilizing properties, is marketed OTC for allergic conjunctivitis.