Theophylline has been used in the treatment of asthma and nal asthma but has now been largely superceded by long-acting inhaled 2-agonists. Nevertheless, theophylline is still useful in chronic obstructive pulmonary disease (COPD) for over 60 years and remains one of the most widely prescribed drugs for the the management of patients with severe asthma. Its benefits have been demonstrated by clinical improvement after addition of treatment of airway diseases worldwide as it is inexpensive. In many industrialized countries, however, theophylline has re- theophylline in patients not controlled even on high doses of inhaled corticosteroids (10) and by the worsening of asthma cently become a third-line treatment that is only used in some poorly controlled patients. This has been reinforced by various when theophylline is withdrawn, despite the continued use of high doses of inhaled and even oral corticosteroids (11, 12). guidelines to therapy. It has even been suggested that theophylline is not indicated in any patients with asthma (1). The fre- Theophylline has also been used as a controller in the management of mild persistent asthma (13), although it is usually quency of side effects and the relatively low efficacy of theophylline have recently led to reduced usage because inhaled 2- found to be less effective than low doses of inhaled corticosteroids (14, 15). Theophylline is currently a less preferred option agonists are far more effective as bronchodilators and inhaled corticosteroids have a greater antiinflammatory effect. Despite than inhaled corticosteroids recommended as a second-line choice of controller in management of patients with asthma the long history of theophylline in asthma therapy, there has been considerable uncertainty about its mode of action in the at Step 2 of the Global Initiative for Asthma Guidelines 2002 guidelines. Although long-acting inhaled 2-agonists are more management of airway diseases and its logical place in therapy. Because of problems with side effects, there have been attempts effective as an add-on therapy at Steps 3 and 4 of the Global Initiative for Asthma Guidelines 2002 guidelines, theophylline to improve on theophylline, and recently there has been increasing interest in the development of selective phosphodiesterase is considerably less expensive and may be the only affordable add-on treatment when the costs of medication are limiting.