T. Fuchsbuder et al., INTERACTION OF MAGNESIUM-SULFATE WITH VECURONIUM-INDUCED NEUROMUSCULAR BLOCK, British Journal of Anaesthesia, 74(4), 1995, pp. 405-409
We have investigated the interaction between magnesium sulphate 40 mg
kg(-1) i.v. and vecuronium. First, we determined the effect of pretrea
tment with magnesium on the potency of vecuronium using a single bolus
dose-response technique. In addition, we compared the time course of
vecuronium-induced neuromuscular block (vecuronium 100 mu g kg(-1)) wi
th and without magnesium pretreatment. For both parts, neuromuscular b
lock was assessed by electromyography. In addition, the effect of magn
esium pretreatment on vecuronium-induced neuromuscular block was inves
tigated in the context of rapid sequence induction of anaesthesia. We
found that the neuromuscular potency of vecuronium was increased by pr
etreatment with magnesium sulphate. The ED(50) and ED(90) of vecuroniu
m with MgSO4 were 25% lower than MgSO4 (ED(50): vs 26.9 mu g kg(-1); 3
4.2 vs 45.7 mu g kg(-1); P < 0.05 for both). Mean onset time was 147.3
(SD 22.2) s in the MgSO4-vecuronium group vs 297.3 (122) s for contro
ls (P < 0.05). Clinical duration was prolonged (MgSO4-vecuronium 43.3
(9) min vs 25.2 (5.1) min for controls; P < 0.05). This was also true
for the recovery index (20.1 (6.6) min vs 10.6 (3.4) min; P < 0.05) an
d duration to 75% recovery (63.4 (9.9) min vs 35.8 (6.9) min; P < 0.05
). in the context of rapid sequence induction, pretreatment with MgSO4
improved the intubating score of vecuronium compared with vecuronium
without MgSO4, reaching the same quality as that with suxamethonium 1
mg kg(-1). We conclude that magnesium pretreatment increased the neuro
muscular potency of vecuronium, in addition to modifying the time cour
se of its neuromuscular block.