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Analgesic Effect of Peripheral Dexmedetomidine

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: September 3, 2009
Last Update Posted: June 8, 2010
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by:
The University of Hong Kong

Dexmedetomidine is an alpha 2-adrenoreceptor agonist, which provides sedation, analgesia and anxiolysis in clinical practice (Cortinez et al., 2004,Hall et al., 2000). Three types of alpha 2-adrenergic receptor subtypes are found in the human body and they have been designated alpha 2A, alpha 2B and alpha 2C. The alpha 2A subtype is most likely responsible for the analgesic properties of dexmedetomidine in both peripheral and central sites (Kingery et al., 2000, Smith et al., 2001). Activation of central alpha 2-adrenoreceptors in the locus ceruleus (Correa-Sales et al., 1992) and the dorsal horn of the spinal cord (Gaumann et al., 1992b) are responsible for both analgesic and sedative effects. Dexmedetomidine has a very high alpha 2 to alpha 1 selectivity, 1620 to 1, or approximately 8 times that of clonidine. It is also 4 to 6 times more potent than clonidine by weight (Bhana et al., 2000).

Although dexmedetomidine produces dose dependent sedation upon intravenous administration, its the analgesic effect is of dexmedetomidine is more variable and controversial. In an ischaemic pain model in healthy volunteers, a single bolus of dexmedetomidine produced a 50% reduction in pain scores when compared to placebo (Jaakola et al., 1991). In another volunteer study using the cold pressor test, dexmedetomidine 1 µg/kg over 10 minutes followed by an infusion of 0.2 to 0.6 µg/kg/hour reduced pain by approximately 30% (Hall et al., 2000). However, when administered as a target controlled infusion at concentrations ranging from 0.09 to 1.23 ng/mL, dexmedetomidine had no analgesic effect in human volunteers subjected to heat and electrical pain, although sedation was produced (Memis et al., 2004).

Clonidine and dexmedetomidine are two common alpha 2 agonists used clinically. Although clonidine former has been used successfully in regional analgesia and anesthesia (Gabriel et al., 2001)., There are only very few studies evaluating the peripheral analgesic effects of dexmedetomidine. Since acute postoperative dental pain is a common analgesia model (Cooper, 1991; US Food and Drug Administration 1992), the investigators conducted this study, aiming to assess the postoperative analgesic efficacy of peripheral dexmedetomidine after bilateral third molar surgery under general anaesthesia. The analgesic effects were compared up to the 72nd hour postoperatively in order to evaluate any potential preventive analgesic effect.

Condition Intervention Phase
Third Molar Extraction Drug: local dexmedetomidine Drug: Peripheral normal saline Drug: IV dexmedetomidine Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effectiveness of Peripheral Dexmedetomidine for Bilateral Third Molar Surgery Under General Anaesthesia

Resource links provided by NLM:

Further study details as provided by The University of Hong Kong:

Primary Outcome Measures:
  • Pain intensity on resting and during mouth opening after dental operation [ Time Frame: 2 years ]

Secondary Outcome Measures:
  • Analgesic consumption, time to first analgesics, side effects, recovery from general anesthesia, satisfaction score [ Time Frame: 2 years ]

Enrollment: 105
Study Start Date: February 2006
Study Completion Date: March 2008
Primary Completion Date: March 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Local Dexmedetomidine Drug: local dexmedetomidine
Preoperative normal saline infusion and 1mcg/kg dexmedetomidine infiltrated locally to wound at the end of operation.
Other Name: Precedex
Placebo Comparator: Normal Saline Drug: Peripheral normal saline
Same volume of normal saline as dexmedetomidine is infiltrated and IV infusion.
Active Comparator: IV dexmedetomidine Drug: IV dexmedetomidine
IV dexmedetomidine 1mcg/kg peroperative and normal saline infiltrated to wound at the end of operation

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Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • American Society of Anesthesiologists (ASA) physical status I and II
  • Age between 18 and 50 years of age with 4 bilateral impacted third molar teeth scheduled for extraction under general anaesthesia

Exclusion criteria:

  • Clinical history or electrocardiographic evidence of heart block
  • Ischaemic heart disease
  • Asthma
  • Sleep apnoea syndrome
  • Impaired liver or renal function
  • Alcohol consumption in excess of 28 units per week
  • Pregnancy
  • Patient refusal
  • Known psychiatric illness
  • Chronic sedative or analgesic use, and regular use of or known allergy to dexmedetomidine, paracetamol or dextropropoxypheneopioids
  • Patients with preoperative inflammation at the site of surgery were also excluded
  Contacts and Locations
No Contacts or Locations Provided
  More Information

Responsible Party: Dr. Chi Wai Cheung, Department of Anaesthesiology, The University of Hong Kong
ClinicalTrials.gov Identifier: NCT00971178     History of Changes
Other Study ID Numbers: 200807176008
First Submitted: September 1, 2009
First Posted: September 3, 2009
Last Update Posted: June 8, 2010
Last Verified: June 2010

Keywords provided by The University of Hong Kong:
Dental pain
Peripheral effects

Additional relevant MeSH terms:
Hypnotics and Sedatives
Central Nervous System Depressants
Physiological Effects of Drugs
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Adrenergic alpha-2 Receptor Agonists
Adrenergic alpha-Agonists
Adrenergic Agonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action