(R)-salbutamol in the treatment of asthma and chronic obstructive airways disease.

INTRODUCTION: Asthma and chronic obstructive pulmonary disease (COPD) are inflammatory disorders that have an increasing prevalence and associated morbidity and mortality. β(2)-adrenoceptor agonists (β(2)-agonists) act by stimulating the β(2)-adrenoceptor present on airway smooth muscle and other cells in the airway, resulting in bronchodilatation. β(2)-agonists are among the most commonly used drugs in the world and remain pivotal in the treatment of symptoms in patients with asthma and COPD. Salbutamol is a chiral drug with (R)- and (S)- isomers. Almost all β(2)-agonists that are used at present are racemic mixtures of (R)- and (S)-salbutamol. AREAS COVERED: In this review the authors show that (R)-salbutamol alone (generically known as levosalbutamol) provides beneficial β(2)-agonist effects at a cellular level and in experimental models of airways disease. In addition the authors demonstrate that (S)-salbutamol opposes the desirable effects of (R)-salbutamol and can actually cause features of asthma and COPD in vitro and in experimental asthma. EXPERT OPINION: Despite this strong body of experimental evidence, (R)-salbutamol has not shown consistent superiority over (S)- or racemic salbutamol in human asthma or COPD.