Interaction of midazolam with two non-depolarizing neuromuscular blocking drugs in the rat in vivo sciatic nerve-tibialis anterior muscle preparation.

Studies of the possible interactions between the water-soluble benzodiazepine, midazolam, and two non-depolarizing neuromuscular blocking drugs, vecuronium and tubocurarine, were performed in the rat in vivo sciatic nerve-tibialis anterior muscle preparation. Midazolam 0.5 and 5 mg kg-1 caused 17% and 34% depression of the twitch height, respectively, once a steady-state blockade of the twitch height had been induced by vecuronium. The potentiation of the tubocurarine steady state blockade by midazolam 5 mg kg-1 was quantitatively equal to that of vecuronium, but was slower in onset. The buffer solvent of midazolam 5 mg kg-1 did not change the steady-state blockade of vecuronium. Midazolam 5 mg kg-1 caused a shift to the left of the cumulative dose-response curves of vecuronium.