Anti-leukotriene therapy in the management of allergic rhinitis

Anti-leukotriene therapy is a relatively new intervention in allergic rhinitis. Allergic rhinitis is a chronic inflammatory disease. This inflammation is partly mediated by leukotrienes. Leukotrienes are synthesized from arachidonic acid when an inflammatory process is triggered. Research has recently focused on developing a new class of drugs that target leukotrienes. These anti-leukotriene drugs can be broadly classified into 2 groups. Leukotriene receptor antagonists inhibit the cysleukotriene receptorl through which leukotrienes C, D and E act to produce inflammation. Leukotriene synthesis inhibitors are drugs that inhibit the synthesis of leukotrienes from arachidonic acid. These drugs may act on various enzymes in the synthesis pathway, such as the 5 lipooxygenase enzyme. Anti-leukotriene therapy has been extensively studied and found to be of benefit in asthma. Research into such therapy in allergic rhinitis has been based on the one-airway, one disease hypothesis. The role of anti-leukotriene therapy is less clearly defined in allergic rhinitis. Recent publications and meta-analyses compare anti-leukotrienes, used singly or in combination, to placebo, anti-histamines, nasal steroids and combination therapy. Anti-leukotrienes are significantly more efficacious than placebo. Data is still equivocal on how they compare to steroids and antihistamines in controlling different symptoms of allergic rhinitis and in improving quality of life. Nasal steroids remain first-line drugs in allergic rhinitis. As a single agent, anti-leukotriene therapy may be used in mild allergic rhinitis. Anti-leukotrienes may also be useful in children and adults in whom steroids may not be acceptable, and as part of multi-modality therapy.