DURATION OF ACTION OF INTRANASAL ATROPINE ON METHACHOLINE-INDUCED NASAL SECRETIONS

Objective: To evaluate the duration of the inhibitory action of intran asal atropine on the secretory response to nasal challenge with methac holine. Design: Double-blind, placebo-controlled, four-way crossover t rial. Subjects: Twelve volunteers with perennial allergic rhinitis. In terventions: Subjects were treated intranasally with placebo or 100, 2 00, and 400 mu g of atropine in each nostril. They were then challenge d 30 minutes after administration of the nasal spray and hourly for 6 hours with 0.19 mg of methacholine. The weight of nasal secretions gen erated by methacholine challenge sewed as an indicator of the secretor y response. The nasal challenges and the collection of nasal secretion s were performed using filter paper disks. Results: After placebo trea tment, the response to methacholine was similar at each time point. In contrast, all doses of atropine significantly reduced the response to methacholine stimulation at the 30-minute, 1-hour, and 2-hour time po ints. Conclusions: Our data show that the anticholinergic activity of intranasal atropine lasts at least 2 hours with no significant differe nce in the duration of inhibitory action between the doses used. The r esults suggest that intranasal atropine could become a therapeutic mod ality for patients in whom glandular hypersecretion is a major symptom .