Single‐Isomer β‐Agonists

A new generation of bronchodilators is being developed for acute asthma management—single‐isomer β‐agonists. These drugs consist only of the active bronchodilatory isomer (eutomer); they do not have the inactive and potentially harmful isomer (distomer) that is present in marketed racemic β‐agonists. Clinical studies comparing the effectiveness of (R)‐albuterol (levalbuterol) with racemic albuterol established a strong rationale for using single‐isomer β‐agonists in place of the racemic mixture: reduced dosages provide equivalent bronchodilatory effects with fewer β‐mediated side effects. Higher dosages achieve superior bronchodilation in episodes of severe asthma and may reduce costs of emergency department treatment.