Meta-analysis of the efficacy of a single dose of phenylephrine 10 mg compared with placebo in adults with acute nasal congestion due to the common cold.

BACKGROUND: Although nonprescription oral phenylephrine 10 mg has been judged "generally recognized as safe and effective" by the US Food and Drug Administration (FDA), its efficacy as a nasal decongestant has been questioned. OBJECTIVE: This study assessed available data on the efficacy of oral phenylephrine 10 mg as a nasal decongestant. METHODS: Three sources were used to identify potentially relevant publications--the bibliography of the phenylephrine section of the 1976 FDA monograph on over-the-counter cold, cough, allergy, bronchodilator, and antiasthmatic products; a 2004 Cochrane Review of nasal decongestants for the common cold; and a search of MEDLINE from 1966 through January 2007 using the term phenylephrine nasal. To be included in the analyses, studies had to have a single-dose, randomized, placebo-controlled design; involve an orally administered product in which phenylephrine 10 mg was the sole active ingredient; enroll patients with acute nasal congestion due to the common cold; evaluate nasal airway resistance (NAR) as the efficacy end point; and have sufficient data in the study report to allow reanalysis and/or meta-analysis of phenylephrine 10 mg versus placebo. Reanalysis of individual studies and fixed-effects and random-effects meta-analyses were performed. Statistical significance at 30 and 60 minutes after dosing (the primary time points) and a >or=20% reduction in NAR from baseline were considered indicative of a clinically meaningful difference. RESULTS: Fifteen potentially relevant studies were identified, of which 8 met the inclusion criteria. Data from 7 crossover studies involving a total of 113 subjects were reanalyzed and then pooled for meta-analysis; results from the initial phase of the eighth study, a parallel-group trial involving 50 subjects, were included in the reanalysis of individual studies but not in the meta-analyses. Significant differences in favor of phenylephrine were seen in 4 of the 8 studies (P or=20% with phenylephrine. CONCLUSION: These meta-analyses of 7 crossover studies and the reanalysis of a parallel-group study support the effectiveness of a single oral dose of phenylephrine 10 mg as a decongestant in adults with acute nasal congestion associated with the common cold.