Drug treatment of asthma in the 1990s: achievements and new strategies.

Asthma is an inflammatory condition of the airways. First-line therapy involves the use of inhaled corticosteroids as anti-inflammatory agents to control the underlying process. Bronchodilators are used for symptom relief. Short-acting beta-agonists provide rapid relief of bronchoconstriction, whereas long-acting beta-agonists control the symptoms and reduce the frequency of exacerbations when combined with inhaled corticosteroids. Anticholinergic bronchodilators have a minor role in acute exacerbations and in patients troubled by adverse effects from beta-agonists. Theophylline has a bronchodilator action in asthma, but its role as an anti-inflammatory agent needs to be examined further. Because of their toxicity, corticosteroid-sparing agents have a limited role, being restricted to patients with severe uncontrolled asthma. New selective phosphodiesterase IV inhibitors show both anti-inflammatory and bronchodilator characteristics with fewer adverse effects. Other new approaches to the control of inflammation come from the antileukotriene drugs, which improve pulmonary function in patients with chronic asthma. The antileukotrienes have shown promising results, especially in the treatment of asthma caused by aspirin (acetylsalicylic acid), exercise and cold air. Other new therapies being studied include anti-immunoglobulin E, antitryptase and anti-CD4 agents. These newer possibilities suggest that the range of available treatment options will expand significantly over the next decade.