Topical ephedrine administration and nasal chemosensory function in healthy human subjects

Objective: To investigate dose-related effects of ephedrine on olfactory fu nction in healthy subjects. Design: Placebo-controlled, randomized, double-blind study. Methods: Drug effects were assessed using olfactory and trigeminal psychoph ysical measures (intensity ratings, odor discrimination, butanol and formic acid thresholds); nasal patency was assessed by means of anterior rhinores istometry. The investigation was performed in 24 healthy volunteers; subjec ts were assigned to treatments A, B, or C (3 groups with 8 subjects each; 4 women and 4 men per group). All subjects received either placebo or ephedr ine in both nostrils; group A subjects received placebo, and group B and C subjects received ephedrine in dosages of 0.12 and 0.24 mg, respectively. Results: Treatment with ephedrine produced a tendency toward an increase of nasal airflow. However, during the time of observation there was no signif icant difference between effects produced by the 2 dosages. Ephedrine had n o systematic effect on measures of olfactory function. The only significant correlation to the nasal airflow was found for perceived intensity of the trigeminal stimuli, which increased with increasing flow. Conclusions: Ephedrine appeared to have neither negative nor major positive effects on intranasal chemosensory function in healthy subjects. This indi cates that ephedrine may be used as a decongestant in studies on olfaction.