Effects of midazolam on fentanyl antinociception and respiration in a rabbit model

Clinical antinociception is difficult to assess because of difficulties with controls and the incorporation of bias. The rabbit antinociceptive model is highly sensitive and predictive of analgesia in humans. We found that the combination of midazolam with fentanyl enhanced antinociception compared with fentanyl alone. In addition, with this model there were relatively unimportant increases in respiratory depression.