A placebo-controlled study of the nasal decongestant effect of phenylephrine and pseudoephedrine in the Vienna Challenge Chamber

Ann Allergy Asthma Immunol. 2009 Feb;102(2):116-20. doi: 10.1016/S1081-1206(10)60240-2.


Background: Studies on the efficacy of phenylephrine in the treatment of nasal congestion have yielded inconsistent results, notwithstanding its approval for this indication.

Objective: To evaluate and compare the decongestant effect of a single dose of phenylephrine to placebo and pseudoephedrine in patients with seasonal allergic rhinitis.

Methods: This randomized, placebo-controlled, 3-way crossover study evaluated patient-scored nasal congestion, peak nasal inspiratory flow, and rhinomanometry at more than 6 hours in 39 grass-sensitive patients exposed to grass pollen in the Vienna Challenge Chamber. Patients were dosed with immediate-release formulations of phenylephrine, 12 mg, pseudoephedrine, 60 mg, as a control, or placebo.

Results: Phenylephrine was not significantly different from placebo in the primary end point, mean change in nasal congestion score at more than 6 hours (P = .56), whereas pseudoephedrine was significantly more effective than both placebo (P < .01) and phenylephrine (P = .01). Phase 1 results showed a difference between phenylephrine and placebo that was 64% of the difference between pseudoephedrine and placebo, substantially greater than the 17% difference observed for all phases. Carryover bias due to patient recall of the pseudoephedrine effect may have influenced these results. Rhinomanometry and peak nasal inspiratory flow results were consistent with these data. Neither phenylephrine nor pseudoephedrine had an effect on the nonnasal symptoms. No adverse events were reported in this study.

Conclusions: During a 6-hour observation period, a single dose of pseudoephedrine but not phenylephrine resulted in significant improvement in measures of nasal congestion. Neither phenylephrine nor pseudoephedrine had an effect on nonnasal symptoms.

Trial registration: ClinicalTrials.gov NCT00276016.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nasal Decongestants / therapeutic use*
  • Phenylephrine / therapeutic use*
  • Placebos
  • Pseudoephedrine / therapeutic use*
  • Rhinitis, Allergic, Seasonal / drug therapy*
  • Time Factors
  • Young Adult


  • Nasal Decongestants
  • Placebos
  • Phenylephrine
  • Pseudoephedrine

Associated data

  • ClinicalTrials.gov/NCT00276016