With the elucidation of
asthma as a chronic inflammatory disease, therapeutic approaches have shifted from treatment of symptoms with
bronchodilators to treatment of the underlying disease with
antiinflammatory agents. Along with concerns about
corticosteroid side effects on the part of both physicians and patients, this shift has motivated researchers to develop and test new agents with antiinflammatory capabilities. The
leukotrienes are endogenous mediators with three inflammatory effects: they increase vascular permeability, recruit other inflammatory leukocytes, and induce bronchoconstriction. A number of antileukotriene agents are in various stages of development.
Zileuton, a
leukotriene synthesis inhibitor, has been shown to improve airway function and reduce
asthma-symptoms, although there is some concern over liver toxicity.
Zafirlukast,
montelukast, and
pranlukast, three new
leukotriene receptor antagonists, have similar benefits and have not been associated with serious increases in liver
enzymes. It is hoped that new antiinflammatory drugs will provide clinicians with targeted and effective
asthma treatments that do not bear the potential risks of
corticosteroid therapy.