Levosalbutamol (also known as levalbuterol), the R-enantiomer of racemic salbutamol (albuterol), is a short-acting β2 adrenergic receptor agonist used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). Salbutamol has been marketed as a racemic mixture, although beta2-agonist activity resides almost exclusively in the (R)-enantiomer. The enantioselective disposition of salbutamol and the possibility that (S)-salbutamol has adverse effects have led to the development of an enantiomerically pure (R)-salbutamol formulation known as levosalbutamol (levalbuterol).