Rahman A R, McDevitt D G, Struthers A D, Lipworth B J
Department of Clinical Pharmacology, Ninewells Hospital, Medical School, Dundee.
Thorax. 1992 Dec;47(12):1056-9. doi: 10.1136/thx.47.12.1056.
Gender differences in the chronotropic effects of infused isoprenaline have previously been described. The aim of the present study was to investigate possible gender differences in hypokalaemic, chronotropic, and electrocardiographic effects of inhaled terbutaline.
Twenty healthy volunteers (10 female) were recruited (mean age 24 years for women (F) and 22 years for men (M). Subjects were given either inhaled terbutaline 5 mg or placebo in single blind, randomised crossover fashion and the following measurements were made for four hours after inhalation: (a) serum potassium concentration; (b) heart rate; (c) electrocardiographic sequelae (T wave amplitude, Q-Tc interval). The effects of terbutaline on serum potassium was chosen as the primary end point for detecting a 0.3 mmol/l difference between sexes, with a beta error of 0.2 and alpha set at 0.05.
The hypokalaemic effects of terbutaline were significantly greater in women, the potassium results (means and 95% CI) being as follows: lowest potassium concentration--F 3.12 (2.96-3.28) mmol/l v M 3.65 (3.49-3.81) mmol/l; percentage change from baseline at one hour--F 15.4% (11.5-19.3%) v M 8.5% (4.6-12.3%); average potassium concentration during the four hours--F 3.39 (3.33-3.46) mmol/l v M 3.78 (3.72-3.85) mmol/l. There was no significant regression between body weight and the potassium response to terbutaline. There were also significant sex differences for T wave, Q-Tc, and heart rate response. The percentage fall in T wave amplitude 30 minutes after terbutaline was: F 44.6% (32.1-57.0%) v M 22.4% (9.9-34.8%).
Women are more sensitive to the hypokalaemic, chronotropic, and electrocardiographic sequelae of inhaled terbutaline.
先前已描述了静脉注射异丙肾上腺素变时效应的性别差异。本研究的目的是调查吸入特布他林在低钾血症、变时和心电图效应方面可能存在的性别差异。
招募了20名健康志愿者（10名女性）（女性平均年龄24岁，男性平均年龄22岁）。受试者以单盲、随机交叉方式接受5毫克吸入特布他林或安慰剂，并在吸入后4小时进行以下测量：（a）血清钾浓度；（b）心率；（c）心电图后遗症（T波振幅、Q-Tc间期）。选择特布他林对血清钾的影响作为检测性别间0.3 mmol/l差异的主要终点，β错误率为0.2，α设定为0.05。
特布他林的低钾血症效应在女性中显著更大，钾的结果（均值和95%可信区间）如下：最低钾浓度——女性3.12（2.96-3.28）mmol/l对男性3.65（3.49-3.81）mmol/l；1小时时相对于基线的变化百分比——女性15.4%（11.5-19.3%）对男性8.5%（4.6-12.3%）；4小时内平均钾浓度——女性3.39（3.33-3.46）mmol/l对男性3.78（3.72-3.85）mmol/l。体重与特布他林的钾反应之间无显著相关性。T波、Q-Tc和心率反应也存在显著性别差异。特布他林后30分钟T波振幅下降的百分比为：女性44.6%（32.1-57.0%）对男性22.4%（9.9-34.8%）。
女性对吸入特布他林的低钾血症、变时和心电图后遗症更为敏感。
