The effects of preanesthetic oral clonidine on total requirement of propofol for general anesthesia.
OBJECTIVE
To 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.


METHODS
Randomized double-blinded study.


METHODS
Operating room ASA physical status I and II room and recovery room of the cancer center.


METHODS
80 breast cancer patients scheduled for surgery.


METHODS
Patients 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.


RESULTS
Preanesthetic 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.


CONCLUSIONS
Preanesthetic 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.
Imai
Y
Y
Department of Anesthesiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
Mammoto
T
T
Murakami
K
K
Kita
T
T
Sakai
T
T
Kagawa
K
K
Kirita
T
T
Sugimura
M
M
Kishi
Y
Y
D000284:Administration, Oral; D000328:Adult; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000191:economics; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001007:Anxiety / Q000517:prevention & control; D001943:Breast Neoplasms / Q000601:surgery; D003000:Clonidine / Q000008:administration & dosage / Q000627:therapeutic use*; D003975:Diazepam / Q000008:administration & dosage / Q000627:therapeutic use; D004311:Double-Blind Method; D016527:Drug Costs; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D007442:Intubation, Intratracheal; D008197:Lymph Node Excision; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009609:Nitrous Oxide / Q000008:administration & dosage; D010100:Oxygen / Q000008:administration & dosage; D010919:Placebos; D011229:Preanesthetic Medication; D015742:Propofol / Q000008:administration & dosage* / Q000191:economics
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D014151:Anti-Anxiety Agents; D010919:Placebos; D009609:Nitrous Oxide; D003000:Clonidine; D003975:Diazepam; D010100:Oxygen; D005283:Fentanyl; D015742:Propofol