Cough originates from a complex in...

Cough originates from a complex interaction between receptors in the airway and the central nervous system; this interaction is poorly understood. Glyceryl ether of guaiacol, commonly known as guaifenesin, is at hand in multiple cough and arctic preparations. This compound has been labeled an expectorant because it is notion to relieve cough by thinning sputum and increasing its production. Guaifenesin is the simply expectorant that has been considered effective by dint of the U.S. Food and mix with drugs Administration. Despite its broad use in the treatment of cough multiple studies have base inconsistent results supporting the effectiveness of guaifenesin as an expectorant or cough suppressant. Little information is available concerning the impact of guaifenesin forward the sensitivity of the cough retroactive Dicpinigaitis and Gayle conducted a randomized, placebo-controlled, double-blind close attention to assess the efficacy of a single dose of guaifenesin upon cough reflex sensitivity.

The trial involved a dispose of persons with acute viral upper respiratory tract infection (URI) and a cluster of healthy persons. The participants were nonsmokers, did not have a history of pulmonary disorders, and had no symptoms suggestive of gastroesophageal ebb disease. Within the previous four weeks, the healthy participants had no URI symptoms, seasonal allergies, or postnasal drip. Participants with URI took no medications to regulate symptoms within at least 24 hours of the study

Each participant received a single 400-mg dose of guaifenesin or placebo single to two hours before undergoing a capsaicin challenge to induce cough The capsaicin challenge was performed with incremental increases in concentration until it induced five or more cough within 15 next to the firsts of inhalation. Spirometry data were aggregateed before the challenge. The main result was the concentration of capsaicin required to induce five or more cough The follows included comparing the effects of guaifenesin and placebo among the patients with URI and the healthy participants.

The URI and healthy clusters each contained 14 persons. All participants were induced to cough during the capsaicin challenge touchstone The spirometry results did not differ between individuals who received guaifenesin and bodily substances who received placebo. Among patients with URI, those who received guaifenesin required significantly higher concentrations of capsaicin to induce cough compared with the placebo assign places to In seven of the 14 participants who received guaifenesin, the concentration necessityed to induce cough was double that of the placebo cluster Among the healthy persons, no differences occurr between the placebo and guaifenesin assign places tos with regard to the concentration of capsaicin that induced five or more coughs

The authors judge that guaifenesin inhibits the cough bent back in patients with URI. This action offers because the cough receptors are transiently hypersensitive secondary to the URI. They add that this drift was not present in healthy persons

KARL E MILLER, MD

Dicpinigaitis PV Gayle YE event of guaifenesin on cough reflected sensitivity. Chest December 2003;124:2178-81.

EDITOR'S NOTE: from one side of to the other the past few years, there has been an increased emphasis onward evidence-based medicine. Because of this emphasis, the efficacy of a certain number of of the older, more established medications has been questioned. common of these medications is guaifenesin. Included in a significant number of cough and cooled preparations, guaifenesin functions mainly as an expectorant. Studies have shown that this medication is an effective expectorant. The application of mind by Dicpinigaitis and Gayle adds to this dead body of literature by demonstrating that guaifenesin also suppresse cough in patients with URI symptoms. This application of mind provides physicians with a proven medication that can restrain the symptoms of URIs and provide supportive care for patients with URIs.--K.E.M.

COPYRIGHT 2004 American Academy of Family Physicians

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