[Does midazolam release histamine?].

Effects of induction with midazolam on serum histamine levels (Study 1) and the volume as well as pH of gastric juice (Study 2) were studied. Anesthesia was induced with midazolam 0.2 mg.kg-1 in midazolam group, thiamylal 4 mg.kg-1 in control group. In Study 1, serum histamine levels were measured with high performance liquid chromatography till 180 minutes after intubation. There were no statistical significance between the two groups in serum histamine levels at all points. But in midazolam group, at 30 minutes after intubation, the histamine level was significantly lower than the preinduction level. In control group, serum concentration of histamine increased but not significantly. In Study 2, gastric juice was sampled through naso-gastric tube inserted on the morning of operation. Gastric juice pH was measured with the use of pH Strip (E. Merck, F.R. Germany). There were no significant differences between the two groups in volume as well as pH of gastric juice at all points. It is concluded that midazolam used for induction of anesthesia might decrease histamine release, but it has no clinical effects on gastric juice secretion.