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

Rigshospitalet

Status and phase: Completed; Phase 4

Conditions: Postoperative Pain; Chlorzoxazone

Treatments: Drug: Placebo; Drug: Zofran; Drug: Chlorzoxazone; Drug: Morphine

Study type: Interventional

Funder types: Other

Identifiers

NCT01933542

SM2-RS-2013

Details and patient eligibility

About

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.

Enrollment: 110 patients

Sex: All

Ages: 18 to 85 years old

Volunteers: No Healthy Volunteers

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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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110 participants in 2 patient groups, including a placebo group

Chlorzoxazone

Active Comparator group

Description:

* 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

Treatment:

Drug: Zofran

Drug: Chlorzoxazone

Drug: Morphine

Placebo

Placebo Comparator group

Description:

* 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

Treatment:

Drug: Zofran

Drug: Placebo

Drug: Morphine