Cannabis Use May Lead to Increased Pain Sensitivity During and Following Surgery

Cannabis is frequently recommended for neuropathic pain and some forms of chronic pain. However, cannabis may not be effective at treating acute forms of pain. In fact, use prior to surgery may lead some patients to require more anesthesia during surgery and increased pain during recovery.


In a first-of-its kind study presented at the ANESTHESIOLOGY 2020 annual meeting, Ian Holmen, MD, the study’s lead author and an anesthesiology resident at the University of Colorado Hospital, Aurora, said, “We now understand patients who chronically use opioids prior to surgery often have exaggerated pain responses and need increased pain medication after surgery because they have an increased tolerance. We speculate that cannabis use may cause a similar effect, but we need more research to determine if this is the case.”


The study involved 118 patients who had surgery at the University of Colorado Hospital to repair a fractured tibia. Of the 118, 30 (25.4%) reported cannabis use prior to surgery, though the researchers did not ask specifics about use (frequency of use, time since last use, type of cannabis used). Researchers then compared the cannabis user group to the non-user group, focusing on:


· Amount of anesthesia used during surgery

· Patient reported pain score

· Opioid dosage following surgery


For each variable, the cannabis user group showed greater pain sensitivity. Most notably, the cannabis user group received 58% more opioids per day than the non-user group.


“This study shows that it is important for patients to tell their physician anesthesiologist if they have used cannabis products prior to surgery to ensure they receive the best anesthesia and pain control possible, including the use of non-opioid alternatives,” said Dr. Holmen. “It also confirms that more research is needed to understand how cannabis impacts pain.”


The American Society of Anesthesiologists has more.

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