• Y Imai, T Mammoto, K Murakami, T Kita, T Sakai, K Kagawa, T Kirita, M Sugimura, and Y Kishi.
• Department of Anesthesiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
• J Clin Anesth. 1998 Dec 1;10(8):660-5.

Study ObjectiveTo investigate the effects of preanesthetic oral clonidine on total propofol requirement for uniform minor surgery (breast conservative surgery: breast cancer removal with axillary lymph node dissection), and to compare the action of clonidine with that of preanesthetic oral diazepam, a commonly used benzodiazepine.DesignRandomized double-blinded study.SettingOperating room ASA physical status I and II room and recovery room of the cancer center.Patients80 breast cancer patients scheduled for surgery.InterventionsPatients were randomized to one of four treatment groups (placebo, clonidine 75 micrograms, or 150 micrograms of clonidine, or 10 mg of diazepam were orally administered 60 min before induction of anesthesia); n = 20 per group. After evaluating the sedation and anxiety levels of patients using a visual analog scale, anesthesia was induced with propofol (1.5 mg/kg), and maintained with oxygen (O2): nitrous oxide (N2O) (30:70) with a continuous infusion of propofol. The propofol infusion was started at 10 mg/kg/h for 10 minutes, then decreased to 8 mg/kg/h, and 6 mg/kg/h thereafter, and the rate of infusion was adjusted to obtain adequate anesthesia (maintaining hemodynamic parameters within 20% of that prior to premedication). Fentanyl 0.2 mg (each 0.1 mg was given for intubation and axillary lymph node dissection, respectively) was administered.Measurements And Main ResultsPreanesthetic oral clonidine (150 micrograms) and diazepam (10 mg) induced anxiolysis without sedation. The total requirement (the mean infusion rates) of propofol in placebo, clonidine 75 micrograms, clonidine 150 micrograms, and 10 mg of diazepam groups were 841 +/- 70 (9.0 +/- 0.3), 720 +/- 63 (7.1 +/- 0.4), 491 +/- 39 (5.6 +/- 0.2), and 829 +/- 77 mg (7.9 +/- 0.4 mg/kg/h), respectively. The cost of propofol in these groups was $51.0 +/- 3.8, $45.5 +/- 3.2, $33.5 +/- 2.3, and $50.5 +/- 4.4, respectively.ConclusionsPreanesthetic oral clonidine (150 micrograms) but not diazepam (10 mg) reduced the total requirement of propofol while stabilizing hemodynamic parameters. In addition, 150 micrograms of oral clonidine attenuates the hemodynamic responses associated with tracheal intubation.

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