Management of asthma and chronic airflow limitation. Are methylxanthines obsolete?
After almost 50 years as first-line drugs in the management of asthma and COPD, methylxanthines have been largely superceded by inhaled adrenoceptor agonist and anticholinergic bronchodilators which are more potent and far less toxic. Accumulating evidence indicates that intravenous theophylline contributes side effects, but is rarely of benefit in acute exacerbations of asthma or COPD. In the maintenance therapy of asthma, first-line therapy is dose-optimized inhaled steroids, reducing the need for bronchodilators. Inhaled adrenoceptor agonists are second line medications, anticholinergic aerosols third line, and theophylline, if needed at all, may fulfill a minor systemic steroid-sparing function in severe asthmatics on maximum doses of the inhaled medications. In the maintenance therapy of some patients with COPD, theophylline sometimes may be useful but these responders should be identified by objectively establishing therapeutic benefit. Since many patients have side effects from the methylxanthines, while their therapeutic benefit over and above dose-optimized inhaled therapy is marginal, their continued almost routine use in the management of reversible airflow obstruction is hard to justify, although this class of drugs may be useful in selected patients in whom both subjective and objective benefit can be demonstrated. In COPD, theophylline may improve exercise capacity in some patients by still incompletely understood mechanisms probably unrelated to bronchodilation.
Lam
A
A
St. Joseph's Hospital, Hamilton, Ontario, Canada.
Newhouse
M T
MT
D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D000628:Aminophylline / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy* / Q000503:physiopathology; D012123:Pulmonary Ventilation / Q000187:drug effects; D013806:Theophylline / Q000627:therapeutic use*
D000305:Adrenal Cortex Hormones; D001993:Bronchodilator Agents; D000628:Aminophylline; D013806:Theophylline