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

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 Overview

• Status: Completed
• Conditions: Postoperative Pain; Chlorzoxazone
• Intervention / Treatment: Drug: Chlorzoxazone; Drug: Morphine; Drug: Zofran; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 110
• Phase: Phase 4

Contacts and Locations

Study Locations

• Denmark
  • Glostrup, Denmark, 2600
    • Glostrup University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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	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
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	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; Drug: Placebo; Two placebo tablets identical to the chlorzoxazone tablets.

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Morphine consumption	Total morphine consumption 0-4 hours after taking the trial medication, administered as patient controlled analgesia (PCA, bolus 2.5 mg, lockout 10 minutes).	0-4 hours after taking the trial medication
Painscore during rest	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.	1, 2, 3 and 4 hours after taking the trial medication
Painscore during mobilization	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.	1, 2, 3 and 4 hours after taking the trial medication
Degree of nausea	Degree of nausea 1, 2, 3 and 4 hours after taking the trial medication.	1, 2, 3 and 4 hours after taking the trial medication
Zofran consumption	Consumption of Zofran (milligram) 0-4 hours after taking the trial medication.	4 hours after taking the trial medication
Degree of dizziness	Degree of dizziness 1, 2, 3 and 4 hours after taking the trial medication.	1, 2, 3 and 4 hours after taking the trial medication
Incidence of vomiting	Total number of vomits 0-4 hours after taking the trial medication.	0-4 hours after taking the trial medication
Degree of sedation	Degree of sedation 1, 2, 3 and 4 hours after taking the trial medication.	1, 2, 3 and 4 hours after taking the trial medication

Collaborators and Investigators

• Sponsor: Rigshospitalet, Denmark
• Collaborators: Glostrup University Hospital, Copenhagen
• Investigators: Principal Investigator: Rikke Soennichsen, MD, Glostrup University Hospital

Study record dates

Study Major Dates

• Study Start: August 1, 2013
• Primary Completion (Actual): August 1, 2015
• Study Completion (Actual): August 1, 2015

Study Registration Dates

• First Submitted: August 23, 2013
• First Submitted That Met QC Criteria: August 30, 2013
• First Posted (Estimate): September 2, 2013

Study Record Updates

• Last Update Posted (Estimate): September 17, 2015
• Last Update Submitted That Met QC Criteria: September 16, 2015
• Last Verified: September 1, 2015

More Information

Terms related to this study

• Keywords: Postoperative pain; Opioid consumption; Spine surgery; Chlorzoxazone
• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Pain; Neurologic Manifestations; Pain, Postoperative; Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Analgesics, Opioid; Narcotics; Neuromuscular Agents; Muscle Relaxants, Central; Morphine; Chlorzoxazone
• Other Study ID Numbers: SM2-RS-2013