Comparison of dexmedetomidine and midazolam sedation and antagonism of dexmedetomidine with atipamezole.
OBJECTIVE
To evaluate the effects of dexmedetomidine, an alpha-2 agonist, as an intravenous sedative drug and the effects of atipamezole, an alpha-2 antagonist, on recovery.


METHODS
Randomized, double-blind study with three parallel groups. An open dose-finding study preceded it to optimize the atipamezole dose.


METHODS
Outpatient operating room at the gynecologic and obstetric university hospital in Helsinki, Finland.


METHODS
Seventy-two healthy women scheduled for legal termination of pregnancy.


METHODS
Patients were assigned to one of three groups of 24 patients each to receive either dexmedetomidine 2 micrograms/kg and atipamezole 50 micrograms/kg; dexmetomidine 2 micrograms/kg and saline; or midazolam 0.15 mg/kg and saline. In addition to paracervical block, each patient received two different study drugs: study drug 1 was a sedative agent (either dexmedetomidine or midazolam), administered before the procedure. If the sedation was not deep enough and the patient reacted to the procedure, a low dose of propofol was administered. Study drug 2 was a reversing agent or a placebo, administered following the procedure.


RESULTS
The mean time to regain consciousness was shorter in the dexmedetomidine-atipamezole and the dexmedetomidine-saline groups compared with the midazolam group. Postoperative sedation, tested both by subjective and objective assessments, decreased more quickly in the dexmedetomidine-atipamezole group compared with the dexmedetomidine-saline and the midazolam groups.


CONCLUSIONS
Atipamezole is an effective antagonist for reversing psychomotor impairment following dexmedetomidine sedation.
Aho
M
M
Department of Anesthesia, Women's Hospital, Helsinki University Central Hospital, Finland.
Erkola
O
O
Kallio
A
A
Scheinin
H
H
Korttila
K
K
D000028:Abortion, Induced; D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage* / Q000037:antagonists & inhibitors*; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000328:Adult; D000762:Anesthesia Recovery Period; D000771:Anesthesia, Intravenous; D001143:Arousal / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003243:Consciousness / Q000187:drug effects; D004311:Double-Blind Method; D005133:Eye Movements / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage* / Q000037:antagonists & inhibitors*; D007093:Imidazoles / Q000008:administration & dosage* / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D020926:Medetomidine; D008874:Midazolam / Q000008:administration & dosage; D010919:Placebos; D011247:Pregnancy; D016138:Walking
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D006993:Hypnotics and Sedatives; D007093:Imidazoles; D010919:Placebos; C050701:atipamezole; D020926:Medetomidine; D008874:Midazolam