Clifton G D, Hunt B A, Patel R C, Burki N K
Division of Clinical Practice, College of Pharmacy, University of Kentucky, Lexington.
Am Rev Respir Dis. 1990 Mar;141(3):575-9. doi: 10.1164/ajrccm/141.3.575.
beta-agonist bronchodilator drugs are known to cause hypokalemia; nevertheless, successive parenteral doses are recommended for the treatment of status asthmaticus. The metabolic and cardiopulmonary effects of sequential, subcutaneous doses of terbutaline were studied in eight stable adult asthmatic patients. Each subject received terbutaline, 0.25 mg subcutaneously, followed 30 min later either by a second subcutaneous dose of terbutaline (sequential) or normal saline (single) in a randomized, double-blind, crossover fashion. Maximum reductions in plasma potassium from baseline were significantly greater (p less than 0.05) following sequential treatment compared to single treatment (-1.1 versus -0.6 mEq/L, respectively). Improvements in forced expiratory volume in 1 s were temporally related to changes in serum potassium and were significantly greater (p less than 0.01) following sequential terbutaline treatment. Prolongation of the QTc interval occurred following both treatment regimens. The change in QTc was statistically significant only following sequential treatment, increasing from 377 +/- 21 to 441 +/- 39 ms (p less than 0.05). Sequential doses of parenterally administered terbutaline result in clinically significant reductions in plasma potassium that are temporally related to changes in pulmonary function and associated with important electrocardiographic alterations.
已知β-激动剂支气管扩张药物可导致低钾血症；然而，对于哮喘持续状态的治疗，仍推荐连续静脉给药。我们对8名病情稳定的成年哮喘患者皮下注射不同剂量特布他林后的代谢及心肺效应进行了研究。每名受试者皮下注射0.25mg特布他林，30分钟后，再以随机、双盲、交叉方式皮下注射第二剂特布他林（连续给药组）或生理盐水（单次给药组）。与单次给药相比，连续给药后血浆钾浓度从基线的最大降幅显著更大（p<0.05）（分别为-1.1和-0.6mEq/L）。一秒用力呼气量的改善与血清钾变化在时间上相关，连续给予特布他林治疗后改善更为显著（p<0.01）。两种治疗方案后均出现QTc间期延长。仅连续给药后QTc变化有统计学意义，从377±21ms增加至441±39ms（p<0.05）。连续静脉注射特布他林可使血浆钾浓度出现具有临床意义的降低，这在时间上与肺功能变化相关，并伴有重要的心电图改变。
