Airway and cardio vascular responses to nebulized glyceryl trinitrate in normal subjects

ABSTRACT

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. 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. 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. Nebulized GTN has cardio vascular effects but does not have any bronchodilator effect in normal subjects. Further investigation in airways disease is justified