International journal of clinical pharmacy
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Randomized Controlled Trial
Inhibition of cough reflex sensitivity by diphenhydramine during acute viral respiratory tract infection.
Currently available over-the-counter cough remedies historically have been criticized for lack of scientific evidence supporting their efficacy. Although the first-generation antihistamine diphenhydramine is classified as an antitussive by the United States Food and Drug Administration, to the authors' knowledge it has never been shown to inhibit cough reflex sensitivity in subjects with pathological cough. ⋯ Our results provide the initial evidence of the ability of diphenhydramine to inhibit cough reflex sensitivity in subjects with acute pathological cough. Timing of cough reflex sensitivity measurement may not have allowed demonstration of maximal antitussive effect of dextromethorphan.