Slattery D, Wong S W, Colin A A
Division of Respiratory Diseases, Children's Hospital, Boston, Massachusetts 02115, USA.
Pediatr Pulmonol. 2002 Feb;33(2):151-7. doi: 10.1002/ppul.10027.
Racemic albuterol, a commonly used bronchodilator, is an exact 50:50 mixture of two enantiomers, R- and S-albuterol. Concern regarding increased mortality associated with the use of this beta-2 (beta 2) agonist triggered the study of both of these enantiomers separately. In vitro studies suggest that the two enantiomers have different binding affinities for beta-adrenoreceptors, may exert opposing effects on inflammation, demonstrate different effects on mucocilary transport, and display differing pharmacokinetics. Clinical studies comparing both enantiomers are few, of short duration, and often in small patient populations, and their results vary. R-albuterol has greater bronchodilatory effects than the racemate and may have anti-inflammatory properties. S-albuterol has markedly less affinity for the beta-adrenoreceptor. It was found to cause bronchoconstriction in animal models, but neither bronchoconstrictive nor pro-inflammatory effects have been conclusively demonstrated in human studies. The data available at present, while suggestive, are insufficient to conclusively recommend R-albuterol over the racemate. Further basic research and investigations in humans comparing both enantiomers at increasing doses over longer time periods are required to clarify the precise roles of R- and S-albuterol.
消旋沙丁胺醇是一种常用的支气管扩张剂，是R-沙丁胺醇和S-沙丁胺醇两种对映体精确的50:50混合物。对使用这种β-2激动剂导致死亡率增加的担忧引发了对这两种对映体的分别研究。体外研究表明，这两种对映体对β-肾上腺素能受体具有不同的结合亲和力，可能对炎症产生相反的作用，对黏液纤毛转运表现出不同的影响，并具有不同的药代动力学。比较这两种对映体的临床研究很少，持续时间短，且患者群体往往较小，其结果也各不相同。R-沙丁胺醇比消旋体具有更强的支气管扩张作用，可能具有抗炎特性。S-沙丁胺醇对β-肾上腺素能受体的亲和力明显较低。在动物模型中发现它会导致支气管收缩，但在人体研究中尚未最终证实其具有支气管收缩或促炎作用。目前可得的数据虽具有一定提示性，但不足以明确推荐使用R-沙丁胺醇而非消旋体。需要进一步开展基础研究以及在人体中进行研究，比较两种对映体在更长时间段内增加剂量时的情况，以明确R-沙丁胺醇和S-沙丁胺醇的确切作用。
