Analgesic Consumption in Chronic Marijuana Users Following Orthopedic Trauma Surgery


Marijuana use has increased since its legalization in Canada and many believe that it may help patients that are experiencing chronic pain. The investigators want to assess if patients who have used marijuana chronically will need more medication to control their pain after they have undergone orthopedic trauma surgery (ex. Hip, femur, humerus fractures etc.). In this study, the investigators will identify chronic marijuana users (ie. those using for 3 months or more) who are undergoing orthopedic trauma surgery to assess how much pain medication they need post-operatively and compare this with non-users. The investigators will also evaluate their pain scores, pain medication use and other complications that they may have during or after their surgeries, including any nausea/vomiting, heart or breathing problems.

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: March 31, 2021

Detailed Description

Since its legalization in Canada, marijuana consumption has become more common while also being the most widely used illicit drug within the USA. In addition to being consumed recreationally, cannabis is being increasingly prescribed by medical practitioners as nearly 15% of Canadian and Australian patients experiencing chronic pain use it as one component of treatment. Recent evidence has demonstrated that specific patient cohorts may benefit from cannabis, including those with fibromyalgia, diabetic neuropathy, complex regional pain syndrome, multiple sclerosis, traumatic neuropathic pain, and difficulty sleeping due to chronic pain, amongst others. Cannabis contains two main components: delta-9-tetrahydrocannabinol (THC), which is active, and cannabidiol, which is inactive. THC has its effects by binding to Type 1 cannabinoid receptors and inhibiting pain pathways while activation of Type 2 cannabinoid receptors have anti-inflammatory properties.

As literature continues to investigate its analgesic characteristics, many proponents of cannabis use believe that it can modify pain response in various settings. One such setting that is of special interest for pain control is during the post-operative period. Currently, there is minimal data available to reflect the analgesic requirement, and thus degree of pain, for a patient who is a chronic marijuana user immediately following a surgical procedure. A class of surgical procedures that is of particular interest to us due to its pain-evoking characteristics is orthopedic trauma surgery. In fact, orthopedic surgeons are one of the higher opioid prescribing specialists, potentially highlighting the difficulty in achieving adequate pain control in their patient population. More information is required to better tailor analgesia for these patients as it may contribute towards their overall recovery, restoring mobility, and patient satisfaction (6,7).

Through this study, the investigators would like to investigate the relationship between orthopedic trauma surgery and post-operative pain control in the chronic marijuana user. Minimal data is available in the literature reflecting this potentially common situation. Specifically, the investigators are interested in the clinical implications of marijuana use on opioid consumption and verbal pain rating in this patient scenario. The investigators also hope that the data can reflect possible side effects or other concerning outcomes in the peri-operative period so that clinicians may be able to provide more personalized care to these patients.

Arms, Groups and Cohorts

  • Non-marijuana user
    • Has never consumed marijuana or has abstained for at least the past 12 months
  • Chronic Marijuana User
    • Has used marijuana in any form at least once a week for the past 3 months

Clinical Trial Outcome Measures

Primary Measures

  • Total opioid consumption
    • Time Frame: Within 24 hours post-operatively
    • The total opioid consumption (morphine equivalents) at 24 hours post-operatively in chronic marijuana users compared to the control group (no marijuana).

Participating in This Clinical Trial

Inclusion Criteria

  • Adults ranging from age 18-75 years old
  • Patients undergoing orthopedic trauma surgery
  • Patients who consent to the study
  • ASA class I to III

Exclusion Criteria

  • Patient refusal
  • Patients lacking capacity to consent
  • Intraoperative regional anesthesia technique
  • Chronic pain patient

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 75 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • University of Alberta
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Vivian Ip, MBChB, Principal Investigator, Staff Anesthesiologist
  • Overall Contact(s)
    • Jaasmit Khurana, MD, 7806161444,

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