Comparative efficacy of inhaled corticosteroids and antileukotriene drugs in asthma

Asthma is an inflammatory disease of the airways that is best treated by mi nimising exposure to factors that provoke the inflammation (e.g. allergens) and by administering drugs that reduce the inflammatory response. The corn erstone of asthma treatment is inhaled corticosteroids. Their effectiveness is a result of their potent and broad anti-inflammatory properties. Antile ukotriene drugs (leukotriene modifiers) provide an alternative and novel ap proach to the treatment of asthma. The novelty of these new compounds is th at their effectiveness is firmly based on the pathophysiology of asthma. sp ecifically the role played by the cysteinyl leukotrienes. At the same time, the availability of the antileukotriene drugs has stirred debate over when they should be used and how they compare to inhaled corticosteroids. Altho ugh the answers are not fully known at this timer the currently available p ublished and presented data are adequate for us to draw some conclusions ab out their relative effectiveness and role in asthma treatment. The antileuk otriene drugs are more effective than placebo, but they are not as effectiv e as inhaled corticosteroids in improving lung function [measured as the fo rced expiratory volume in 1 second (FEV1) or peak expiratory flow rate (PEF R)], reducing beta (2)-agonist use, and decreasing symptom-free days. In co ntrast, they may have similar beneficial effects on reducing asthma exacerb ations and decreasing peripheral blood eosinophil counts. In the absence of knowing a priori the response of an individual patient to treatment with e ither therapy, the data Favour initiating treatment with an inhaled cortico steroid. However, for patients with mild to moderate disease there are a nu mber of circumstances that support using an antileukotriene drug first. A f ew examples are aspirin intolerance, predominantly exercise-induced symptom s and problems with using an inhaler or the adverse effects of inhaled cort icosteroids such as dysphonia and thrush. For patients with more severe dis ease, inhaled corticosteroids remain the treatment of choice. Antileukotrie ne drugs should be considered as add-on therapy, especially in view of thei r possible complementary effects on reducing airway inflammation.