Comparison of Midazolam and Thiopental as an Induction Agent

Chung, Yoon Jae; Lee, Myung Suk; Kim, Hye Kyung

Abstract

Midazolam is a new water soluble benzodiazepine which used to induce anesthesia. The drug possesses properties similar to those of benzodiazepines(sedative, anxiolytic, anticonvulsant, muscle-relaxant) and has low toxicity compared with thiopental which is world-wide used for induction agent. Midazolam is characterized by slow onset of action, more gradual effects on circulation, low frequency of thrombophlebitis and greater degree of antegrade amnesia. Because of these characteristics midazolam is used as an alternative induction agent. As an induction agent, in order to evaluate the properties of midazolam compared with thiopental, 60 patients were divided into 2 groups. Group I, thiopental 5 mg/kg induction group; Group II, midazolam 0.15mg/kg induction group. Systolic and diastolic blood pressure, pulse rate, induction time and recovery time were measured in each group. Frequency of the throm bophlebitis, retrograde and antegrade amnesia were evaluated. In group I, systolic blood pressure decreased significantly and pulse rate increased signifi-cantly. In group II, diastolic pressure decreased significantly and pulse rate increased signifi-cantly. Induction time and recovery time were delayed significantly in group II than group I. In group II, frequency of the thrombophlebitis was lower and antegrade amnesia was greater than group I. Retrograde amnesia did not occured in both groups. On the basis of these data, midazolam used for induction maintains hemodynamic stability, induces anesthesia smoothly, produces low frequency of the thrombophlebitis and high frequency of antegrade amnesia. Therefore it is concluded that midazolam is safe and effective induction agent and may offers an advantage over thiopental in situations where hemodynamic stability is crucial.