Pretreatment with Dexmedetomidine or Thiopental Decreases Myoclonus after Etomidate: A Randomized, Double-Blind Controlled Trial

Background

Myoclonic movements are common problems during induction of anesthesia with etomidate. The aim of this study was to compare the effect of pretreatment with dexmedetomidine (0.5 μg/kg) and thiopental (1 mg/kg) on the incidence of etomidate- induced myoclonus and postoperative pain.

Materials and Methods

A prospective double-blind study was conducted at a university hospital. Ninety patients (ASA physical status I-II) were randomly assigned to one of three groups: patients were pretreated with either dexmedetomidine (0.5 μg/kg), thiopental (1mg/kg), or saline before induction of anesthesia with etomidate. One minute after the injection of study drugs, etomidate, 0.3mg/kg was given. Myoclonus was assessed on a scale of 0 to 3. Recovery time, postoperative pain score, and hemodynamic variables were recorded during the intraoperative and postoperative period. Headache, nausea, vomiting, and coughing were noted during the study.

Results

The incidence and the intensity of myoclonus was significantly lower in the dexmedetomidine and thiopental groups (34%, 36%) than in the control group (64%) (P<0.05). The postoperative pain score at 30min in the thiopental group was significantly higher than in the dexmedetomidine and control groups (63%) (P<0.05).

Conclusions

We concluded that pretreatment with dexmedetomidine or thiopental is effective in reducing the incidence and severity of etomidate-induced myoclonic muscle movements and pretreatment with thiopental increases the postoperative pain.

Key Words: etomidate, myoclonus, dexmedetomidine, thiopental, hyperalgesia