Midazolam And Fentanyl Interactions With Emulsified Isoflurane

Midazolam Hypnotic Interaction with Emulsified IsofluraneEmulsified isoflurane is a new drug under investigation at the preclinical stage. It is developed and owned with the intellectual property by the Laboratory of Anesthesia and Critical Care Medicine, West China Hospital, Sichuan University. It is manufactured by Huarui Pharmaceutical Corporation. Results from the preclinical studies demonstrated that emulsified isoflurane was eliminated from the lungs after intravenous administration. It is safe and has no apparent side effects on major organs in rats and dogs. Moreover, this formulation has advantages of rapid induction and recovery during anethesia. Therefore, it might be a good candidate for intravenous anesthesia. As an intravenous general anesthetic, emulsified isoflurane is administered in combination with midazolam, which is commonly used in induction. The objective of this study was to examine the effects of different doses of midazolam on ED50 of emulsified isoflurane and to define the type of interaction between them during hypnosis in rats. METHODS: A total of 125 male adult Sprague-Dawley rats (240-300 g) were included in the study. The rats were grouped into 5 depending on the drug(s) administered via the tail vein. The up-and-down sequential allocation technique was used to determine ED50 of midazolam in the loss of the righting reflex. According to the results, the up-and-down sequential allocation technique was also used to determine ED50 of emulsified isoflurane combined with different midazolam doses of 6.5 mg/kg (1/4 ED₅₀), 13 mg/kg (1/2 ED₅₀) and 19.5 mg/kg (3/4 ED₅₀), respectively, as well as with no combination of midazolam in the loss of the righting reflex. Midazolam...