ABSTRACT
I. Introduction Asthma and chronic obstructive pulmonary disease (COPD) are complex syndromes of airway inflammation. Asthma is a disease of the small airways of the lung. Intermittent narrowing of the respiratory bronchioles produces airway limitation and the symptoms of wheezing, chest tightness, and breathlessness. By contrast, in COPD the limitation of airflow is poorly reversible and usually gets progressively worse over time. The disease is primarily, but not exclusively, seen in smokers and former smokers. Environmental and genetic factors contribute to the etiology of both diseases. Cigarette smoking is the main risk factor for COPD, although less than 20% of chronic heavy smokers will develop symptoms of airway obstruction (1). Bronchodilators and corticosteroids are currently the most common medications used in the treatment of asthma and COPD.
