Airway and Cardio Vascular Responses to Nebulized Glyceryl Trinitrate in Normal Subjects

Background: glyceryl trinitrate (gtn) is a potent smooth muscle relaxant and vasodilator. there are conflicting reports regarding its efficacy as a bronchodilator. the aim of this study was to examine the effect of nebulized gtn on airway calibare and cardio vascular system in normal subjects. methods: we studied 24 normal subjects (6 female) on two occasions, administering either nebulized gtn 6 mg or placebo in a double-blind, randomized, crossover fashion. bronchial response was assessed by measurement of fev1. results: a systemic effect of this dose of gtn was demonstrated by a supine to erect increase in heart rate of 36.0 (8.6) % mean (95% ci) after gtn compared with 16.2 (6.1) % after placebo. systolic blood pressure (bp) decreased by 8.0 (3.8) % after gtn compared with 1.4 (2.8) % after placebo. diastolic bp did not change. baseline fev1 did not differ on the two study days. there was no acute bronchodilator effect. conclusions: nebulized gtn has cardio vascular effects but does not have any bronchodilator effect in normal subjects. further investigation in airways disease is justified.