Additive effect of nitroglycerine inhalation on beta2-agonist-induced bronchodilatation in asthmatics.
The current treatment of airway obstruction using beta-agonists and theophylline is designed to increase intracellular level of cAMP. Experimental data show that cGMP and cAMP induce functionally additive relaxation of airways. Nitrates relax smooth muscle through the activation of guanylate cyclase. We wondered whether an additive effect of nitroglycerin (NTG) on beta2-agonist-induced bronchodilatation was present in asthmatic patients. To this aim we evaluated the acute bronchodilating effect of inhaled salbutamol (200 mu g MDI) in 10 asthmatics, pre-treated with inhaled NTG or placebo, in a double-blind cross-over design. FEV1 after NTG was higher than that obtained after placebo (2197 +/- 175 vs. 1981 +/- 155 ml, P <0.001). Mean FEV1 obtained 5 min after salbutamol was higher when patients were pre-treated with NTG than placebo (2694 +/- 217 vs 2440 +/- 228 ml respectively, P <0.001). The bronchodilatation due to salbutamol was identical whether NTG or placebo was inhaled first, respectively at 458 +/- 68 and 497 +/- 44 ml after 5 min. After 15 min FEV1 was higher than baseline, but no significant difference was still present between the value observed after pre-treatment with NTG or placebo (2554 +/- 235 and 2551 +/- 205 ml respectively). In conclusion, in asthmatics nebulized NTG produces a moderate and short-lasting bronchodilatation, which is additive with that produced by salbutamol.
Rolla
G
G
Dipartimento di Scienze Biomediche e Oncologia Umana, University of Torino, Italy.
Brussino
L
L
Colagrande
P
P
Bucca
C
C
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000420:Albuterol / Q000494:pharmacology*; D000704:Analysis of Variance; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D014665:Vasodilator Agents; D005996:Nitroglycerin; D000420:Albuterol