A Randomized, Double Blind, Placebo-controlled Three-way Crossover Study in Mild Asthmatics to Evaluate the Effect of Smoking Status on the Attenuation by Inhaled Corticosteroids of the Allergen-induced Asthmatic Response.

Detailed Summary

People with asthma suffer from breathlessness because the small tubes (bronchioles) that carry air in and out of the lungs become inflamed and narrow. Steroids reduce the inflammation, and are commonly used to control asthma, but they do not work well in some asthmatics, particularly those who smoke. This study is done to find out more about why smokers with asthma do not benefit from steroid treatment. In this study, the effect of Flixotide (fluticasone propionate), a steroid widely used to treat asthma, is tested in smokers and non-smokers with mild asthma. 16 smokers and 16 non-smokers, aged 18-55 years will be enrolled in this study. Subjects will take each of the following treatments: * 100 micrograms Flixotide twice daily for 7 days; * 500 micrograms Flixotide twice daily for 7 days; and * placebo (dummy medicine) twice daily for 7 days. Study design: subjects will have a screening visit (over 2 days), and will take part in 3 treatment periods (which are separated by interval of at least 14 days); a follow-up visit is scheduled 7 days after the last intake of study treatment. The order in which order the subjects will take the treatments is defined at random. Total study duration: about 11 weeks. To test the effects of Flixotide, the subject's responses to : * an inhaled allergen test * a PC20 methacholine test * blood, urine and sputum PD markers will be analysed. This study will take place in 2 centres: 1 in the United Kingdom and 1 in Belgium. The units will recruit participants by advertising (newspaper, radio, and websites), word of mouth, from volunteer databases, and via the centres' websites.

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Interventions