The effect of lidocaine on the neuromuscular junction and the interaction between lidocaine and the muscle relaxant, succinylcholine(SCC) or vecuronium(VEC), were investigated in 12 cats of either sex using the sciatic nerve-anterior tibialis muscle preparation. The degree of twitch depression with lidocaine itself was 16.43+/-14.94%, and the ED from dose-response curves of SCC and VEC(8.35+/-4.62 and 6.36+/-8.03 ug/kg, respectively) in group II (under lidocaine infusion) were smaller than those(20.57+/-15.80 and 8.98+/-7.31 ug/kg) in group I (without lidocaine). There was no difference in the duration of action of SCC and VEC between the two groups, but the onset of VEC in group II was longer than in group I(p<0.05), The mean arterial pressure(MAP) after lidocaine infusion was reduced 149.17 to 130.83mmHg and MAPs at the same dose of each agent were also lower in group II than in group L The authors conclude that lidocaine itself produces the twitch depression and potentiates the SCC-or VEC-induced neuromuscular block. However, there is no influence on the duration of SCC or VEC.
Animals ; Cats* ; Depression ; Drug Interactions ; Lidocaine* ; Neuromuscular Blockade* ; Neuromuscular Junction ; Succinylcholine* ; Vecuronium Bromide*