Effectiveness of Midazolam in the Prevention of Etomidate Induced Myoclonus

Introduction: Etomidate, the imidazole derivative, is an intravenous anaesthetic induction agent, having stable hemodynamic profile, minimal respiratory side effects and histamine release. It is extremely useful in hemodynamically compromised patients. But the most common problem associated with its induction is myoclonus. Objective: To determine the effect of pretreatment with midazolam on the frequency of myoclonus after etomidate induction. Methods: Two hundred and fifty patients fulfilling the inclusion and exclusion criteria, scheduled for elective surgical procedures, were included. After all monitoring and intravenous access, the patients were given intravenous midazolam 0.05 mg/kg and after ninety seconds anesthesia induction was done with etomidate, and the myoclonic movements were noted for a minute after etomidate injection. The movement were recorded and graded on a scale of 0 to 3. Results: Myoclonus was developed in 15.45% (38/246) cases while in 84.55% (208/246) patients abnormal muscle movements was not observed after etomidate injection. Mild myoclonus (grade 1) was observed in 23 (9.3%) cases, moderate myoclonus (grade 2) in 11 (4.5%) and severe (grade 3) in 4 (1.6%) cases. Summary: The incidence of myoclonus was lowered significantly (15.45%) after 0.05mg/kg midazolam pretreatment.