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ABSTRACT
Airway mucus hypersecretion and increased oxidative stress are clinical and pathophysiological features of asthma exacerbation. We studied effects of N-acetylcysteine (NAC) as a mucolytic and antioxidant agent in asthma exacerbation.
In this randomized, single-blinded, placebo-controlled study 50 patients ( 17 male, 33 female, mean age 48.94±13.68) with asthma exacerbation were randomized to receive either oral 600 mg b.d. N-acetylcystiene or placebo in addition to standard treatment during 5 days hospitalization. Daily measurements of wheezing, dyspnea, cough, sputum, expectoration, night sleep scores and morning PEFR were performed.
There was no significant difference in wheezing score between patients assigned NAC and those assigned placebo in day 5(0.84[SD 0.94] VS 0.87[SD 0.79]) and also in cough score (0.72[SD 0.84] VS 0.79[SD 0.97]), dyspnea score (0.84[SD 1.06] VS 0.91[SD 1.01]), sputum score(0.79[SD 0.83] VS 0.62[SD 0.71]), expectoration score(0.79[SD 0.97] VS 0.83[SD 1.09]), night sleep score(1[SD 1.17] VS 0.67[SD 0.98] and morning PEFR (256[SD 96.36] VS 282[SD 98.86]).
We concluded that addition of N-acetylcysteine to usual asthma medication has no significant effect in treatment of asthma exacerbation.
Key words: Antioxidant; Asthma; Mucus hypersecretion; Mucolytic; N-acetylcysteine
INTRODUCTION
Airway mucus overproduction and mucus plugging with airflow obstruction are pathophysiologic features of asthma and contribute not only to airway hyperresponsivness but also to morbidity and mortality of this disease.1-5 Difficulty in clearing of airway mucus has been demonstrated in most asthmatic patients.6
On the other hand oxidant/antioxidant imbalance have been shown in asthma7-9 as a consequence of chronic airway inflammation. 10 The oxidants can also amplify inflammation in asthmatic airways with many pathophsiological effects including mucus hypersecretion.11 Asthma severity and acute exacerbation of asthma are associated with increased oxidative sress.1,12
N-acetylcysteine (NAC) breaks disulfate bonds and is one of the most effective agents for reducing sputum viscosity. 13-15 NAC as a mucolytic agent may be able to produce a modest improvement in symptoms and lung function by altering the mucus secretion and its physical properties in asthma.16
NAC also is a thiol antioxidant which has the potential to interact either directly with oxidant or indirectly by replenishing depleted glutathione stores. NAC can block the release of inflammatory mediators from epithelial cells and macrophages, inhibit adhesion molecules, and also inhibit neutrophil chemotaxis, activation and aggregation.17-19 The antioxidant protective effect of NAC can...