The Effect of Chlorzoxazone on Moderate to Severe Postoperative Pain After Spine Surgery

Overview

Chlorzoxazone is a centrally acting muscle relaxant used to treat muscle spasm and the resulting pain or discomfort. It acts on the spinal cord by depressing reflexes. Our purpose is to investigate the effect of chlorzoxazone on moderate to severe postoperative pain after spine surgery. Our hypothesis is that chlorzoxazone can reduce postoperative pain and reduce opioidconsumption and side effects compared to placebo.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: August 2015

Interventions

  • Drug: Placebo
    • Two placebo tablets identical to the chlorzoxazone tablets.
  • Drug: Chlorzoxazone
    • Two 250 mg chlorzoxazone tablets
  • Drug: Morphine
    • Patient controlled intravenous morphine (PCA-pump), bolus 2.5 mg, lock-out-time 10 minutes. Concentration : Morphin 1 mg/ml.
  • Drug: Zofran
    • Zofran 4 mg iv. in case of moderate to severe nausea, supplemented by Zofran 1 mg iv. if needed

Arms, Groups and Cohorts

  • Active Comparator: Chlorzoxazone
    • Oral administration of chlorzoxazone 500 mg (two 250 mg tablets) Morphine. Patient controlled intravenous morphine (PCA-pump), bolus 2.5 mg, lock-out-time 10 minutes. Concentration : Morphin 1 mg/ml. Zofran 4 mg iv in case of moderate to severe nausea, supplemented by Zofran 1 mg iv if needed
  • Placebo Comparator: Placebo
    • Oral administration of two placebo tablets Morphine. Patient controlled intravenous morphine (PCA-pump), bolus 2.5 mg, lock-out-time 10 minutes. Concentration : Morphin 1 mg/ml. Zofran 4 mg iv in case of moderate to severe nausea, supplemented by Zofran 1 mg iv if needed

Clinical Trial Outcome Measures

Primary Measures

  • Painscore during mobilization
    • Time Frame: 2 hours after taking the trial medication
    • Painscore during active mobilization (VAS scale) defined by a standarized movement from recumbent position to sitting on the bedside

Secondary Measures

  • Morphine consumption
    • Time Frame: 0-4 hours after taking the trial medication
    • Total morphine consumption 0-4 hours after taking the trial medication, administered as patient controlled analgesia (PCA, bolus 2.5 mg, lockout 10 minutes).
  • Painscore during rest
    • Time Frame: 1, 2, 3 and 4 hours after taking the trial medication
    • Painscore at rest (VAS)at time 1, 2, 3 and 4 hours, calculated as area under curve (AUC) from 1-4 hours after taking the trial medication.
  • Painscore during mobilization
    • Time Frame: 1, 2, 3 and 4 hours after taking the trial medication
    • Painscore during active mobilization (VAS scale) defined by a standarized movement from recumbent position to sitting on the bedside at time 1, 2, 3 and 4 hours, calculated as area under curve (AUC) from 1-4 hours after taking the trial medication.
  • Degree of nausea
    • Time Frame: 1, 2, 3 and 4 hours after taking the trial medication
    • Degree of nausea 1, 2, 3 and 4 hours after taking the trial medication.
  • Zofran consumption
    • Time Frame: 4 hours after taking the trial medication
    • Consumption of Zofran (milligram) 0-4 hours after taking the trial medication.
  • Degree of dizziness
    • Time Frame: 1, 2, 3 and 4 hours after taking the trial medication
    • Degree of dizziness 1, 2, 3 and 4 hours after taking the trial medication.
  • Incidence of vomiting
    • Time Frame: 0-4 hours after taking the trial medication
    • Total number of vomits 0-4 hours after taking the trial medication.
  • Degree of sedation
    • Time Frame: 1, 2, 3 and 4 hours after taking the trial medication
    • Degree of sedation 1, 2, 3 and 4 hours after taking the trial medication.

Participating in This Clinical Trial

Inclusion Criteria

  • Patients undergoing spine surgery in general anaesthesia. – Postoperative pain > 50 mm on the VAS scale during mobilization. – Patients who have not received analgesia 1 hour prior to inclusion. – ASA 1-3. – BMI > 18 og < 40. – Fertile women need a negative HCG urine test. – Patients who have given their written consent to participate and understand the contents of the protocol. Exclusion Criteria:

  • Participation in another clinical trial. – Patients who do not speak and/or understand Danish. – Fertile women with a positive HCG urine test. – Allergy to the drugs used in the trial. – Alcohol or medicine abuse, assessed by investigator. – Daily use of strong opioids (morphine, ketobemidone, oxynorm, methadone, fentanyl) – Daily chlorzoxazone treatment. – Known or suspected porphyria.

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 85 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Rigshospitalet, Denmark
  • Collaborator
    • Glostrup University Hospital, Copenhagen
  • Provider of Information About this Clinical Study
    • Principal Investigator: Rikke Vibeke Nielsen, MD, MD – Rigshospitalet, Denmark
  • Overall Official(s)
    • Rikke Soennichsen, MD, Principal Investigator, Glostrup University Hospital

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