CLONIDINE DECREASES THE DOSE OF THIAMYLAL REQUIRED TO INDUCE ANESTHESIA IN CHILDREN

Clonidine is a useful drug to give preoperatively because it produces anxiolysis, sedation, and hemodynamic stability, and reduces intraveno us and volatile anesthetic requirements. Several premedicants, includi ng midazolam and diazepam, have been shown to reduce the induction dos e of intravenous anesthetics, such as thiopental, ketamine, or propofo l. A randomized, double-blind controlled study was conducted to evalua te the effect of premedication with oral clonidine on thiamylal requir ement for the induction of anesthesia and on associated hemodynamic ch anges in children. Sixty children (ASA grades I-II, 7-12 yr old) were assigned randomly to receive one of three treatments (n = 20, for each group): placebo (control), clonidine 2 mu g/kg, or clonidine 4 mu g/k g 105 min before the induction of anesthesia. Thiamylal was injected a t a dose of 1 mg/kg every 15 s until loss of the eyelash reflex and th e dose was recorded. Blood pressure (BP), heart rate (HR), and arteria l oxygen saturation were recorded every minute from the beginning of i njection of thiamylal for 5 min. Significant decreases in thiamylal do se were observed in patients receiving clonidine. The induction dose o f thiamylal (mean +/- SD) was 5.4 +/- 0.9, 4.5 +/- 1.1, and 3.4 +/- 0. 9 mg/kg for patients receiving placebo, clonidine 2 mu g/kg, and cloni dine 4 mu g/kg, respectively (P < 0.05). Systolic BP decreased by 6.8% , 5.6%, and 6.6% and HR increased by 5.7%, 4.8%, and 4.1% after admini stration of thiamylal in the control (placebo) group and the clonidine 2 mu g/kg and clonidine 4 mu g/kg groups, respectively (P > 0.05). Pr emedication with oral clonidine reduced the dose of intravenous thiamy lal required for the induction of anesthesia in children.