Chronic inflammatory diseases of the lungs, including asthma and chronic obstructive pulmonary disease (COPD), are common pulmonary causes of morbidity and mortality. Although triggered by somewhat different mechanisms, both result in cell-mediated inflammation in the lungs (predominantly, eosinophilic in asthma and neutrophilic in COPD), leading to manifestations of increased bronchial smooth muscle tone, increased bronchial wall thickness, excess secretion of mucus, and (in the case of COPD) loss of elasticity of lung parenchyma. Chronic inflammatory disease patients experience the typical symptoms of cough and dyspnea. Various medications are used both singly and in combination to reduce chronic inflammation, and thereby relieve symptoms associated with asthma and COPD.
This group of medications includes oral steroids (eg, prednisone, prednisolone), inhaled steroids (budesonide, fluticasone, flunisolide, beclomethasone), and parenteral steroids (methylprednisolone). Corticosteroids are potent suppressants of markers of inflammation including interleukins, chemokines, and TNF-alpha.
Inhaled corticosteroids are used for maintenance treatment of asthma and COPD, while oral and IV steroids are generally reserved for treatment of exacerbations. Routine use of inhaled corticosteroids helps to decrease airway inflammation and reactivity; over time this can improve symptoms as well as lung function. Inhaled agents are commonly used in management of mild to moderate asthma and also in COPD, although steroids have been noted to be less effective in COPD patients. According to findings of prior studies, it is possible that this is due to several mechanisms of corticosteroid resistance at the cellular level.
Anticholinergics include the short-acting drug ipratropium bromide (Atrovent) and the long-acting drug tiotropium bromide (Spiriva). They relax bronchial smooth muscle to produce bronchodilation. They mostly affect the larger, central airways in the lung.
Anticholinergics are often used in conjunction with beta-2 adrenergic agonists, as this combination has shown to be more effective than either agent used alone. Anticholinergics have a slower time to onset but a longer duration of action than beta-2 agonists.
These drugs fall into two categories: leukotriene receptor antagonists and leukotriene synthesis inhibitors. Montelukast (Singulair) and zafirlukast are both receptor antagonists while zileuton is a synthesis inhibitor.
Leukotrienes are potent bronchoconstrictors (1000 times greater than histamine); thus blocking their actions would have a benefit in opening tight airways. Leukotriene modulators have been used as an adjunct treatment for moderate to severe asthma.
Theophylline is the best-known drug of this class. Methylxanthines inhibit bronchoconstriction mediated by cyclic adenosine monophosphate (cAMP); they are nonspecific phosphodiesterase inhibitors.
These medications were once commonly used, but have fallen out of favor due to their narrow therapeutic window (requiring frequent blood level monitoring) and numerous side effects, including abdominal pain, nausea, vomiting, diarrhea, headaches, arrhythmias, palpitations, tremor, and seizures. Occasionally, these drugs are used as adjunct medication for more severe asthma and COPD.