Does injection of non-depolarizing neuromuscular blockers before thiopentone affect their speed of onset? A study of tubocurarine and vecuronium.

In an open sequential pharmacodynamic study in 40 patients, the rate of onset of neuromuscular blockade using tubocurarine or vecuronium was measured. Comparison was made between groups of 10 patients who received thiopentone followed by either blocker and a "reverse" sequence where the blocker was injected before thiopentone. There was a small difference between groups, amounting to a few seconds in rate of onset of block, but this was not suggestive of a systematic effect of the drug sequence.