Anesthesiology
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Clinical studies suggest that midazolam and propofol interact synergistically to induce hypnosis, but these drugs do not interact synergistically to prevent movement in response to noxious stimuli. The mechanisms underlying these interactions are not certain but may occur at the level of the gamma-aminobutyric acid A (GABA(A)) receptor. ⋯ The interaction between midazolam and propofol was critically dependent on the concentration of GABA: Synergism was evident at low concentrations of GABA, but an additive interaction was apparent when the concentration of GABA was increased. Changes in GABA(A) receptor function may underlie the synergistic interaction between propofol and midazolam for clinical effects such as hypnosis. The clinical implication of the results is that the benefits of synergism observed at one concentration ratio of these drugs may not be apparent at another.