1.1 Background
Asthma is characterized by airway and lung tissue inflammation and airway hyperresponsiveness (AHR) that leads to recurrent symptoms of wheezing, breathlessness, chest tightness, and coughing. AHR indicates an exaggerated response of the airway to nonspecific stimuli, which results in a temporary airflow limitation, leading to airway obstruction. It remains unknown which factors within the airway of an individual trigger reversible airway obstruction and airway narrowing. The airway epithelium is composed of many interacting structural components and inflammatory cells. The number, activation, and secretory component of inflammatory cells in the airway are altered in the disease. In asthma, the number of eosinophils and T lymphocytes is increased in the subepithelial layer.
The impact of asthma has traditionally been measured in terms of the prevalence of the disease, mortality rates, and levels of healthcare utilisation, particularly hospital admissions. However, the impact of asthma extends beyond these outcomes to include effects on lifestyle, wellbeing, and perceived health status. Adults of working age with asthma have poorer health status and quality of life outcomes than those with no asthma. This effect is independent of confounding by sociodemographic and life style factors and is evident across a range of dimensions of quality of life. In comparison with two other chronic health conditions, asthma has a larger adverse impact on health status and quality of life than diabetes.
1.2. Investigational Agent
Montelukast reversibly inhibits cysteinyl leukotrienes (CysLTs), specifically leukotrienes D4 (LTD4 \[3\]. LTD4 is the most potent bronchoconstricting agent on a molar basis, but Cys-LTs also have chemoattractive properties for many inflammatory cells (mainly eosinophils), effects on vascular permeability, mucous secretions and sensory nerve activation, and are responsible for part of the pathophysiology of asthma.
1.3. Dose Rational/Risk \& Benefit
Montelukast is a potent and selective blocker of the CysLT1 receptor. For treatment of chronic asthma, montelukast is administered once daily to adults as a 10-mg film-coated tablet, to children aged 6-14 years as a 5-mg chewable tablet, and to children aged 2-5 years as a 4-mg chewable tablet form. Given their efficacy, antiinflammatory activity, oral administration, and safety, leukotriene modifiers will play an important role in the treatment of asthmatic patient. Side effects most commonly reported above placebo included headache, otitis media, upper respiratory infection, and pharyngitis.
