Managing asthma: past, present, and future.

Asthma has been recognized in the medical literature for almost 2000 years. Modern pharmaco-therapy for asthma began with the commencement of the 20(th) century following the development of epinephrine and the demonstration of its effectiveness for acute symptoms of asthma. Progressive development of this class of bronchodilator medication has provided greater β2 specificity and longer duration of action. Corticosteroids were introduced about 50 years ago. As a systemic medication, they provided anti-inflammatory activity that continues to be essential for exacerbations of symptoms that are unresponsive to a bronchodilator. Corticosteroids were subsequently developed as inhaled agents for long-term maintenance therapy. The availability of corticosteroids with high topical effect has permitted the use of smaller doses with minimal systemic effect; therefore, the inhaled corticosteroids have become the most effective monotherapeutic agents for chronic asthma.Both theophylline and long-acting β2 agonists (e.g., salmeterol) provide additive clinical effect to small doses of inhaled corticosteroids. This effect is greater than that achieved with larger doses of the inhaled steroid used alone. A new approach to managing allergic asthma is now available in the form of a monoclonal antibody directed against immunoglobulin E (IgE). This agent, omalizumab, binds to circulating IgE, thereby preventing IgE from binding to mast cells. This subsequently prevents the release of mediators for bronchospasm and inflammation. Under investigation are monoclonal antibodies to modify the effects of interleukins involved in the inflammatory process of asthma. Phosphodiesterase inhibitors that are more specific than theophylline and monoclonal antibodies that prevent the attachment of rhinovirus to respiratory mucosa are being studied. Since rhinoviruses are major causes of acute exacerbations of asthma, these and other measures to prevent or modify the common cold provide great potential for further improvement in the outcome of asthma.