Asthma Asthma affects approximately 22 million individuals in the United States, including 6% of children (239). It is characterized by a history of episodic wheezing, physiologic evidence of reversible obstruction of the airways either spontaneously or following bronchodilator therapy, and pathologic evidence of chronic inﬂammatory changes in the bronchial submucosa. Asthma is not a disease of airway physiology in which hypertrophy and increased contractility of bronchial smooth muscle is the dominant lesion; rather, it is an inﬂammatory disease affecting the airways that secondarily results in epithelial damage, leukocytic infiltration, and increased sensitivity of the airways to a number of stimuli. The treatment of asthma is directed toward relaxing the airways and alleviating inﬂammation (239).
Multiple stimuli are noted to precipitate or exacerbate asthma, including environmental allergens or pollutants, respiratory tract infections, exercise, cold air, emotional stress, nonselective beta-adrenergic blockers, and NSAIDs (239). Management of asthma includes removal of the inciting stimuli as well as use of appropriate pharmacologic therapy. The optimal therapy for asthma involves managing the acute symptoms and long-term management of the inﬂammatory component of the disease.
Pharmacotherapy of Asthma
The treatment of asthma is divided into long-term control modalities and short-term modalities.
Recognizing the underlying pathophysiology in asthma as an inﬂammatory condition, inhaled corticosteroids are the cornerstone for maintenance therapy. Onset of action is slow (several hours), and up to 3 months of steroid therapy may be required for optimal improvement of bronchial hyperresponsiveness. Even with acute bronchospasm, steroid treatment can enhance the beneficial effect of beta-adrenergic treatment. During acute exacerbations of asthma, a short course of oral steroids, in addition to inhaled steroids, may be necessary. For adults with chronic asthma, only a minority will require chronic oral steroid therapy. Patients taking oral steroids should receive intravenous steroid support in the form of 100 mg of hydrocortisone IV every 8 hours perioperatively, sharply tapering within 24 hours of surgery to avoid adrenal insufficiency. Other long-term control therapies include (239): 1.
Leukotriene modifiers (i.e., montelukast): These agents interfere with leukotrienes, substances released from mast cells, eosinophils, and basophils important in the inﬂammatory response.
2.
Cromolyn sodium: Highly active in the treatment of seasonal allergic asthma in children and young adults. It is usually not as effective in older patients or in patients in whom asthma is not allergic in nature.
3.
Immunomodulators: Omalizumab, a monoclonal antibody to immunoglobulin E (IgE), has gained support for prevention and may be an important adjunct in symptomatic suppression.
4.
Long term beta2-adrenergic agonists (i.e., salmeterol): Although not appropriate for single agent management or use in mild disease, they are an important adjunct in the suppression of symptoms in patients with significant disease.
5.
Methylxanthines (i.e., theophylline): These were relegated to third-line status in the management of asthma. Theophylline toxicity can develop when other drugs such as ciproﬂoxacin, erythromycin, allopurinol, Inderal, or cimetidine are concomitantly administered. Therapeutic serum levels must be monitored closely.