Influence off haemodilution on the potency of neuromuscular blocking drugs

The potencies of suxamethonium, pancuronium, and tubocurarine were increased, as shown by a parallel shift to the left of cumulative dose-response curves, following normovolaemic haemodilution before operation. This is attributed to an increase in cardiac output, to a decrease in protein binding and, in the case of suxamethonium, to a decrease in cholinesterase activity.