EFFECT OF ORAL CLONIDINE PREMEDICATION ON INTRAVENOUS ANAESTHETICS

OBJECTIVES: To study the effect of oral clonidine premedication on the induction doses of intravenous thiopentone sodium and propofol. METHODS: After ethical committee approval and informed consent, 120 ASA grade I and II patients were randomly allocated to four groups of 30 each. Group A received a placebo orally, 90 minutes before induction with thiopentone. Group B received clonidine 4 mu g/kg orally, 90 minutes before induction with thiopentone. Group C received a placebo orally, 90 minutes before induction with propofol. Group D received clonidine 4 mu g/kg orally, 90 minutes before induction with propofol. The patients were premedicated with Tab Diazepam 5 mg orally on the night before surgery. Inj. Glycopyrrolate 0.004 mg/kg IV was administered before starting anaesthesia. The patients were pre-oxygenated with 100% oxygen for 3 minutes and anaesthesia was induced with either thiopentone sodium 2.5% or propofol, slowly till loss of eyelash reflex was achieved. The dose of either thiopentone sodium or propofol required for induction of anaesthesia was noted. Inj. Succinylcholine 1.5 mg/kg was injected intravenously to facilitate tracheal intubation and after intubation anaesthesia was continued in the conventional manner. The heart rate and blood pressure were recorded throughout the procedure. RESULTS: The dose of thiopentone sodium required for induction was significantly lower by 21.3% in the group B (3.65 +/- 0.3 mg/kg) as compared with the control group A (4.64 +/- 0.35 mg/kg), effect size, d = 2.02, p < 0.001. The dose of propofol required for induction was significantly lower by 16.01% in the group D (1.73 +/- 0.08 mg/kg) as compared with the control group C (2.06 +/- 0.06 mg/kg), effect size, d = 0.92, p = 0.001. CONCLUSION: Oral clonidine premedication decreases the induction doses of both thiopentone sodium and propofol.