POSSIBLE INTERACTION BETWEEN EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE AND THERAPY IN CHILDREN WITH ASTHMA

1. The aim of the study was to determine the carbachol and albuterol r esponsiveness in treated and untreated asthmatic and allergic children exposed to environmental tobacco smoke assessed by urinary cotinine m easurements. 2. Forty-six asthmatic and allergic children with normal spirometric values were recruited. The doubling dose, concentration of carbachol producing a 2-fold increase in specific airway resistance ( SRaw) was determined and 200 mu g of albuterol were administered via a Volumatic(R) spacer. The percentage of bronchodilatation was defined as the difference between the largest obtained SRaw and the post-a SRa w divided by the largest SRaw. Data were compared by a Mann-Whitney U- test. 3. The 23 children with a high urinary cotinine, compared with t he 23 children without urinary cotinine, had a decreased doubling dose (108.2 +/- 14.7 mu g versus 160.9 +/- 19.5 mu g; P = 0.04) and an inc reased percentage of bronchodilatation (74.8 +/- 1.4% versus 68.8 +/- 1.8%; P = 0.03). A prophylactic anti-inflammatory treatment induced a weaker bronchial reactivity to carbachol and a slightly greater bronch odilatation in children exposed to environmental tobacco smoke. 4. Env ironmental tobacco smoke increases bronchial reactivity in asthmatic a nd allergic children. This effect might be reduced by anti-inflammator y therapy. The bronchodilator response may be enhanced in exposed chil dren and may be caused by one or several direct interactions between t obacco smoke compounds and albuterol.