Effect of halothane on tubocurarine and suxamethonium block in man.

The effect of halothane 2 per cent on neuromuscular transmission and its interaction with both tubocurarine and suxamethonium was investigated in twenty patients undergoing surgery, using the twitch response to ulnar nerve stimulation. Ventilation was constantly controlled throughout the procedure. Halothane did not cause any depression of the twitch response in the absence of tubocurarine; a slight increase was even observed. On the other hand, when halothane was inhaled during tubocurarine block, a marked depression of the twitch was observed. Suxamethonium produced intense fasciculations when injected during halothane anaesthesia, but no significant difference in the degree of block was observed.