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The Labyrinth of Asthma Therapy

The pharmacologic treatment of asthma, which began centuries ago, has recently gained complexity at logarithmic rates. Centuries ago, the Chinese inhaled 3-agonists from herbs containing ephedrine. Thousands of years later, in the 17th century, anticholinergic asthma treatments from Datura species were discovered, and these gained dominance until more refined adrenergic drugs evolved. Adrenaline was first used in asthma treatment at the turn of the 19th century. Then came the age of oral corticosteroids, which were found to be helpful and, in many instances, life-saving. With their success, however, came a plethora of serious side effects; it became evident that long-term systemic steroid therapy was a suboptimal solution.

The evolution of pharmacotherapy accelerated, and selective 32-agonists were developed, with the promise of fewer adrenergic side effects. With the latter half of the 20th century came the introduction of inhaled steroids, which have now become first-line therapy for persistent asthma. Even more recently, long-acting selective 32-agonists and leukotriene inhibitors have been added to the asthma armamentarium. At present, patient care involves choices between different classes of drugs, different drugs in a class, different delivery mechanisms, different treatment intervals, and different combinations between, and within, classes of drugs. The number of combinations and permutations is considerable.

How then does one formulate therapeutic plans for asthmatics? Conceptual simplification is necessary. First, we must define the goals of asthma therapy. The major goals are to prevent the loss of pulmonary function and to improve the quality of life, and to achieve both with minimal adverse effects from the therapy. Effecting and maintaining good pulmonary function is the foundation that promises a cascade of benefits, including symptom control, improved exertional capacity, and decreased exacerbations. These in turn effect decreased patient costs and decreased costs to society at large, via both decreases in absenteeism and decreases in hospitalizations (the most expensive part of asthma care). Airway inflammation has now been shown to be the major pathophysiologic finding in asthma. The therapeutic dominance of inhaled steroids is directly related to their capacity to reduce airway inflammation and improve pulmonary function, leading to decreases in symptoms and exacerbations with an acceptable side-effect profile at the doses usually utilized.