[Safety and tolerability of bronchodilators in chronic obstructive pulmonary disease].

The most effective bronchodilators in chronic obstructive pulmonary disease (COPD) are beta(2)-adrenergic and anticholinergic agents. When administered via inhalation and at recommended doses, these drugs are well tolerated and generally safe. beta-Adrenergic agents show systemic effects such as an increase in heart rate, QT prolongation, hypopotassemia and tremor. These effects have little clinical significance. Nevertheless, patients with cardiac comorbidity or respiratory insufficiency can be at greater risk of arrhythmia and other adverse cardiac events. Long action beta(2)-adrenergic agents have not been shown to increase mortality in COPD. The most frequent adverse effect of anticholinergic agents is dryness of the mouth; these drugs also increase the risk of glaucoma and urinary retention. Anticholinergic agents may increase cardiovascular risk, although the evidence is inconsistent. The use of methylxanthines is limited by frequent gastrointestinal adverse effects and by the narrow therapeutic range of these drugs.