Several sympathomimetic drugs are used primarily as vasoconstrictors for local application to the nasal mucous membrane or the eye: propylhexedrine (benzedrex, others), naphazoline (privine, naphcon, others), oxymetazoline (afrin, ocuclear, others), and xylometazoline (otrivin, others) [see Table 10-1]. Ethylnorepinephrine (bronkephrine) is a b agonist that is used as a bron-chodilator; the drug also has a agonist activity, which may cause local vasoconstriction and thereby reduce bronchial congestion. Phenylephrine (see above), pseudoephedrine (sudafed, others) (a stereoisomer of ephedrine), and phenylpropanolamine are sympathomimetics used most commonly in oral preparations for the relief of nasal congestion. Pseudoephedrine is available without a prescription in a variety of solid and liquid dosage forms. Phenylpropanolamine shares the pharmacological properties of ephedrine and is approximately equal in potency except that it causes less CNS stimulation. The drug has been available over-the-counter (OTC), and numerous proprietary mixtures marketed for the oral treatment of nasal and sinus congestion contain one of these sympathomimetic amines, usually in combination with an H1 histamine antagonist. Because phenylpropanolamine increases the risk of hemorrhagic stroke, most manufacturers have voluntarily stopped marketing products containing phenylpropanolamine in the U.S. and the FDA is withdrawing approval for the drug.
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