Kume M, Kashimoto S, Kumazawa T
Department of Anaesthesiology, Yamanashi Medical College, Japan.
Eur J Anaesthesiol. 1992 May;9(3):223-8.
The effects of mexiletine on cardiac function and myocardial metabolism were assessed in the isolated rat heart-lung preparation. Mexiletine 1, 2, 4 or 8 micrograms ml-1 was administered 5 min after the start of perfusion. Heart rate decreased in the 2, 4 and 8 micrograms ml-1 groups significantly following the drug administration. The highest dose of mexiletine reduced cardiac output significantly, and this dose was associated with a higher incidence of dysrhythmias than the other groups. Although there was no significant difference in myocardial glycogen concentration among groups, ATP contents in the 4 micrograms ml-1 and 8 micrograms ml-1 groups were significantly less than in the control group. Lactate contents in the 4 micrograms ml-1 and 8 micrograms ml-1 groups were significantly higher than in the control group. Generally, the therapeutic plasma concentration of mexiletine is 0.5-2.0 micrograms ml-1. These results suggest that mexiletine may have a lesser margin of safety than lignocaine.
在离体大鼠心肺制备模型中评估了美西律对心脏功能和心肌代谢的影响。灌注开始5分钟后给予1、2、4或8微克/毫升的美西律。给药后，2、4和8微克/毫升组的心率显著下降。美西律的最高剂量显著降低了心输出量，且该剂量组心律失常的发生率高于其他组。尽管各组之间心肌糖原浓度无显著差异，但4微克/毫升和8微克/毫升组的ATP含量显著低于对照组。4微克/毫升和8微克/毫升组的乳酸含量显著高于对照组。一般来说，美西律的治疗血浆浓度为0.5 - 2.0微克/毫升。这些结果表明，美西律的安全范围可能比利多卡因小。
