Aims: The effects of a single dose of oxymetazoline nasal spray on nasal patency have been compared with placebo using three separate measuring systems in normal subjects.
Methods: The study was a placebo-controlled, randomised double-blind crossover trial. Subjects without ear, nose or throat disease and with resting nasal airways resistance >0.15 Pa s cm-3 were selected so that a fall in airways resistance could be detected. Nasal airways resistance (NAR) was measured by NR6-2 rhinomanometer. Acoustic rhinometry (SR-2000 rhinometer) provided the sum of the minimum cross-sectional areas (tMCA) and volume (tVOL) of the left and right nasal cavities. Symptoms of congestion were assessed on a visual analogue scale (CON, range 0-100). Measurements were made for 60 min before and for 120 min after bilateral administration of oxymetazoline nasal spray (0.9 mg) or placebo (0.9% saline). Crossover occurred 7-21 days later. Results for all measures were analysed as change from average baseline value by trapezoidal AUC, and statistical significance was tested by 2-way anova.
Results: NAR, tMCA, tVOL and CON did not change after placebo, but NAR and CON fell and tMCA and tVOL increased significantly at all timepoints after oxymetazoline. NAR_AUC, tVOL_AUC, tMCA_AUC were significantly different between placebo and oxymetazoline (P<0.001) as was CON_AUC (P=0.012). The day-to-day intraindividual repeatability of baseline NAR tMCA and tVOL was <10%.
Conclusions: Normal subjects can be used to detect the effects of nasally vasoactive drugs with a variety of complementary systems, with the advantages of easy subject recruitment and low variability.