Effect of doxapram on neostigmine evoked antagonism of vecuronium neuromuscular block.

We have examined the effect of doxapram on neostigmine-evoked antagonism of vecuronium neuromuscular block in a double-blind study in anaesthetized patients. Neuromuscular transmission was measured with a Datex Relaxograph. The mean time to recovery of the first contraction of the train-of-four (T1) from 25% to 75% was significantly longer in the presence of doxapram (138 (SEM 21) s; n = 23) than in its absence (95 (13) s; n = 29) (P = 0.014). The recovery of the train-of-four ratio was prolonged also in the presence of doxapram, although this difference was not statistically significant.