Objective measurement of the analgesic effect of midazolam in humans.

The effect of midazolam sedation on late evoked potentials (EPs) elicited from painful stimulation of the median nerve was investigated in 20 human volunteers. EPs were recorded from the contralateral scalp at baseline and at 5, 30, and 60 min post-midazolam infusion. Relative amplitudes of the late EPs were significantly reduced after intravenous midazolam infusion and did not return to normal during the 60 min of the experiment. Given the correlation between EP amplitude and subjective reports of experimental pain, the data support the suggestion that midazolam may have some analgesic effect.