Bronchial asthma

today and tomorrow

Abstract

Asthma is characterized by reversible obstruction, inflammation, and hyperreactivity of the airways. The diagnosis is based on clinical information and pulmonary function tests. Eosinophils are a main feature of the asthma pathophysiology. They produce bronchoconstrictor, chemotactic, and vasoactive products that lead to hyperreactivity. Also, they damage surrounding tissue, by releasing their cytotoxic granule content. The recommendations for the treatment of asthma were organized around four components of effective asthma management: use of objective measures of lung function to assess the severity of asthma and to monitor the course of therapy; environmental control measures to avoid or eliminate factors that precipitate asthma symptoms or exacerbations; comprehensive pharmacologic therapy for long-term management designed to reverse and prevent the airway inflammation characteristic of asthma as well as pharmacologic therapy to manage asthma exacerbations; and, patient education that foster a partnership among the patient, family, and clinicians. The

b2-adrenergic agonists are the most commonly used class of drugs for the treatment of asthma. Using this drug on an as-needed basis is now more frequently accepted and recommended. In acute asthma, a b2-adrenergic agonist is still the medication of choice. Long-acting, salmeterol and formoterol, administered only twice daily, can decrease symptoms of asthma during day and nighttime. Theophylline, whose use has been limited by the potential for serious toxicity, may regain an important position in the asthma treatment with the development of the knowledge about its antiinflammatory actions. Dosing theophylline on a time-related basis also improves the risk/benefit ratio and makes theophylline a useful drug for nocturnal asthma. Ipratropium bromide, an anticholinergic drug, still awaits a defined role in the treatment of asthma. Corticosteroids, including inhaled forms, have measurable effects on symptoms, lung function, bronchial responsiveness, and inflammation associated with asthma. Side-effects of chronic use limit systemic administration, but not inhaled administration. Newer preparations, like budesonide, flunisolide, and fluticasone decrease the incidence of possible side-effects related to inhaled steroids by having better ratio of topical to systemic potency. Newly released medications include anti-leukotrienes (LTs) agents which function either by blocking the interaction of LTs with receptors (receptor antagonists) or by inhibiting leukotriene synthesis (synthesis inhibitors). Representatives of the antagonists discussed here are zafirlukast, pranlukast, and montelukast. Pranlukast, the first leukotriene receptor antagonist to be marketed, improves lung fuction and symptons when 450 mg b.i.d. is used. Zileuton, a leukotriene synthesis inhibitor, has been shown to improve lung fuction, reduce symptoms, reduce use b-agonists and asthma exacerbations. These positive effects are dose dependent and liver function abnormalities seem to be a relevant issue during zileuton use in some patients.