(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. βÎ2-adrenoceptor agonists (βÎ2-agonists) act by stimulating the βÎ2-adrenoceptor present on airway smooth muscle and other cells in the airway, resulting in bronchodilatation. βÎ2-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 βÎ2-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 βÎ2-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.