Effects of oral clonidine premedication on side effects of intravenous ketamine anesthesia: a randomized, double-blind, placebo-controlled study.
OBJECTIVE
To determine the effects of oral clonidine premedication on hemodynamic changes during the entire course of ketamine anesthesia and incidence of postoperative adverse reactions.


METHODS
Randomized, prospective, double-blind, placebo-controlled study.


METHODS
Department of Anesthesiology, University of Tsukuba Hospital, Ibaraki, Japan.


METHODS
39 ASA physical status I and II patients undergoing superficial surgeries.


METHODS
Placebo, clonidine 2.5 micrograms/kg, and clonidine 5 micrograms/kg groups received respective doses of oral clonidine 90 minutes prior to surgery. Anesthesia was induced with ketamine 2 mg/kg intravenously (i.v.), trachea was intubated, and anesthesia was maintained with 67% nitrous oxide, oxygen, and supplemental ketamine (1 mg/kg) when systolic blood pressure and heart rate (HR) exceeded 180 mmHg and 100 bpm, respectively.


RESULTS
In the clonidine 2.5 micrograms/kg group, HR response to tracheal intubation was significantly less, while in the clonidine 5 micrograms/kg group both mean arterial pressure and HR responses were significantly suppressed, compared with the placebo group. Intraoperative coefficients of variations of HR were significantly less in both clonidine groups than the placebo group. Incidence of nightmare and degree of salivation were significantly less in the clonidine 5 micrograms/kg group than in the placebo group.


CONCLUSIONS
Oral clonidine 2.5 micrograms/kg and clonidine 5 micrograms/kg attenuates cardiostimulatory effects, while clonidine 5 micrograms/kg was associated with reduced incidence and severity of nightmare and salivation attributable to i.v. ketamine.
Handa
F
F
Department of Anesthesia, Akita University School of Medicine, Japan.
Tanaka
M
M
Nishikawa
T
T
Toyooka
H
H
D000284:Administration, Oral; D000328:Adult; D000771:Anesthesia, Intravenous; D000778:Anesthetics, Dissociative / Q000009:adverse effects*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects; D003000:Clonidine / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D004325:Dreams / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D015994:Incidence; D007442:Intubation, Intratracheal; D007649:Ketamine / Q000009:adverse effects*; D008297:Male; D016343:Monitoring, Intraoperative; D009609:Nitrous Oxide / Q000008:administration & dosage; D010100:Oxygen / Q000008:administration & dosage; D010919:Placebos; D011183:Postoperative Complications; D011292:Premedication; D011446:Prospective Studies; D012472:Salivation / Q000187:drug effects; D013565:Sympatholytics / Q000008:administration & dosage / Q000627:therapeutic use*
D000778:Anesthetics, Dissociative; D018685:Anesthetics, Inhalation; D010919:Placebos; D013565:Sympatholytics; D007649:Ketamine; D009609:Nitrous Oxide; D003000:Clonidine; D010100:Oxygen