Corticosteroids and leukotrienes: chronobiology and chronotherapy

Corticosteroids and leukotrienes play opposite roles in asthma. Corticosteroids, both endogenously secreted and exogenously administered, are antiinflammatory and are very effective in the treatment of asthma. They have also been evaluated chronotherapeutically and have been found to be very effective in reducing the enhanced airway inflammation and decrement in lung function associated with nocturnal worsening of asthma. Leukotrienes are potent proinflammatory and spasmogenic mediators that have been shown to be increased at night in patients with nocturnal asthma (NA). Leukotriene modifiers, a new class of medications to treat asthma, improve, but do not abolish, the symptoms and decrement in lung function associated with nocturnal asthma. However, they have not been evaluated chronotherapeutically. This article addresses the roles of corticosteroids and leukotrienes in nocturnal asthma and their position as therapeutic agents or targets for therapy.