Relative and Additional Bronchodilator Response of Salbutamol and Ipratropium in Smoker and Nonsmoker Asthmatics

PURPOSE: This study was conducted in the Department of Tuberculosis and Respiratory Diseases, J. N. Medical College, Aligarh, India, from January 2006 to December 2007. The fact that smoker asthmatics can behave like chronic obstructive pulmonary disease (COPD) patients encourages the researcher to therapeutically exploit the important cholinergic influence in these patients. To clarify the clinical importance of the issue, the present nonblind and nonrandomized study was aimed at relative bronchodilator response to adrenergic and cholinergic agents. METHODS: Ninety-six patients of asthma, 48 nonsmokers and 48 smokers, were given sequential doses of inhaled salbutamol and after achieving maximum bronchodilation, ipratropium was administered to observe the additional bronchodilation. On the next day, the sequence of drugs was reversed. Ipratropium was given first and after achieving maximal response, salbutamol was given. RESULTS: On giving salbutamol first, maximal improvement in forced expiratory volume in one second (FEV(1)) was 67.04% +/- 12.98% in nonsmokers and 60.64% +/- 13.6% in smokers. The additional improvement with ipratropium was 9.22% +/- 2.08% in smokers and was significantly higher (p <.001) than in nonsmokers (0.13% +/- 2.14%). When ipratropium was given first, maximum improvement in FEV(1) was 41.95% +/- 4.57% in smokers, which was significantly higher (p <.001) than in nonsmokers (20.06% +/- 7.06%). The additional improvement with salbutamol was 23.16% +/- 5.07% and 19.09% +/- 4.9%, respectively, in nonsmokers and smokers. CONCLUSIONS: With the above results, the authors concluded that in smoker asthmatics, cholinergic tone was more prominent and there was down-regulation of adrenergic receptors, as both drugs caused significant additional dilatation. So in smoker asthmatics, addition of a cholinergic agent will result in better control of asthma. In nonsmoker asthmatics, addition of cholinergic agent is of little or no value.