PURPOSE: We had previously shown that the final common pathway of autonomic control of bronchomotor tone in asthma is through adrenoceptors and all the achievable bronchodilation was obtained with adrenergic agents (Jindal SK. Respiration 1989;56:56–21). The present study was undertaken to see whether there was any differential responsiveness of smoker asthmatics to salbutamol (S) and ipratropium bromide (IB) administration.
METHODS: We studied 30 patients of chronic stable asthma equally grouped into current smokers (Sm) and life time nonsmokers (NS). Smoking and bronchodilators were withheld 24 hours prior to the study while inhalational steroids were continued. After baseline spirometry, sequential doses of one agent, S or IB were given through a metered dose inhaler and a spacer to achieve the fullest expression of a particular neuronal mechanism (adrendergic or cholinergic) reflected by a plateau on the dose response (FEV1 and FVC) curves after which the other agent was administered for any additional bronchodilatation. The sequence of drug administration was reversed in the next experiment after 2 days.
RESULTS: Significant increases were seen in PEF and the spirometry indices following administration of either S or IB (Table 1). But the additional increases following the administration of second agent after a plateau response with the first was not statistically significant in both NS and Sm patients (Table 1), except that NS patients receiving IB first showed a better additional increment in FEV1 after S as compared to Sm patients.
CONCLUSION: The bronchodilatory responses of both NS and Sm to supramaximal doses of either S or IB were generally similar.
CLINICAL IMPLICATIONS: There is no additional bronchodilatory advantage of combining S and IB in either NS or Sm asthmatics.
DISCLOSURE: Surinder Jindal, No Financial Disclosure Information; No Product/Research Disclosure Information