Shiner R J, Molho M I
Chest. 1983 Apr;83(4):602-6. doi: 10.1378/chest.83.4.602.
Fifteen patients suffering from asthma received inhalations of phentolamine, albuterol (salbutamol), a combination of phentolamine and albuterol, and placebo, in a single-blind fashion; the changes in the pulmonary function tests were recorded over a three-hour period. Three patients responded to phentolamine with marked bronchodilatation, whereas severe bronchoconstriction was induced by the drug in two patients. Five patients improved more with phentolamine than with placebo, while all patients improved more markedly with albuterol and still more following inhalation of the combination of both drugs. As a group, there were no statistically significant differences between the responses to phentolamine compared with placebo, or between albuterol alone compared with the combination of both drugs. We concluded that both alpha-antagonist and beta 2-agonist agents act in the same direction in most patients, the beta 2-agonist being the dominant. These results do not offer convincing proof that enhanced alpha-adrenergic activity is the main bronchoconstrictor mechanism even in those few with good response to phentolamine, who also showed very good responsiveness to albuterol. The mechanism of phentolamine-induced bronchoconstriction was discussed, but in the light of presently accepted theories, we were unable to evolve a reasonable explanation.
15名哮喘患者以单盲方式接受了酚妥拉明、沙丁胺醇、酚妥拉明与沙丁胺醇的组合以及安慰剂的吸入治疗；在三小时内记录肺功能测试的变化。3名患者对酚妥拉明有明显的支气管扩张反应，而2名患者用药后出现严重支气管收缩。5名患者使用酚妥拉明比使用安慰剂改善更明显，而所有患者使用沙丁胺醇后改善更显著，吸入两种药物的组合后改善更甚。作为一个整体，与安慰剂相比，对酚妥拉明的反应之间，或单独使用沙丁胺醇与两种药物组合之间的反应，在统计学上没有显著差异。我们得出结论，在大多数患者中，α拮抗剂和β2激动剂的作用方向相同，β2激动剂起主要作用。这些结果并没有提供令人信服的证据表明，即使在那些对酚妥拉明反应良好的少数患者中，增强的α肾上腺素能活性是主要的支气管收缩机制，这些患者对沙丁胺醇也表现出非常好的反应性。讨论了酚妥拉明诱导支气管收缩的机制，但根据目前公认的理论，我们无法得出合理的解释。
