Lidocaine modifies changes in muscle oxygen consumption and blood flow induced by succinylcholine

The effects of succinylcholine (Sch) 2mg/kg alone and in combination with lidocaine (4.5mg/kg) on muscle oxygen consumption (Vo_2) and muscle blood flow (MBF) in normal and denervated gastrocnemius muscle were studied in 18 dogs anesthetized with halothane. In additional five dogs with normal gastrocnemius muscle, the effects of lidocaine alone on Vo_2 and MBF were also studied. In normal muscle, Sch increased significantly Vo_2 for 15 min, the maximum increase being 145% above the control value (1.12±0.25ml/min/100g). The conmbination of Sch and lidocaine did not increase Vo_2. Attenuation of the increase in Vo_2 due to Sch was considered as the results of lidocaine's effects on both pre^- and post junctional membrane. MBF was not changed by Sch. Neither the Vo_2 nor MBF was affected by lidocaine alone. In denervated muscle, Sch increased Vo_2 and MBF for 10 min, the maximum increase 299% and 105% above the control value (1.50±0.13 and 38.9±6.1ml/min/100g), respectively. With the combined use of Sch and lidocaine the Vo_2 and MBF increased up to 349% and 288% above the control value (1.77±0.17 and 29.2±2.6ml/min/100g), respectively. The invreases in Vo_2 and MBF due to Sch were augumented with the combined use of lidocaine. These results indicate differential effects of lidocaine on muscular response to Sch in normal and denervated muscle, and suggests that lidocaine should be included among agents that modify the supersensitivity phenomenon produced by Sch in denervated muscle.