Medical Marijuana Offers Little Benefit for Acute Pain

By Roger Chriss, Columnist

Colorado lawmakers are considering a bill that would let doctors recommend cannabis for short-lived acute pain. According to the Denver Post, the bill would allow doctors to recommend marijuana for any condition “for which a physician could prescribe an opiate for pain.”

State law currently allows Colorado doctors to recommend marijuana for nine long term medical conditions, including severe chronic pain. But Dr. Larry Wolk, the executive director of the Colorado Department of Public Health and Environment, cautioned that there isn’t enough evidence to support marijuana’s use for acute pain.

“We’re not set up … for this acute pain situation,” Wolk said at a hearing. “This would last maybe three days to a week. But, when you receive a (medical marijuana) card, it’s good for a year.”

Cannabis is one of the most studied substances in the world, but many basic questions about its medical use remain unexplored. Research has found that cannabis doesn’t work well for acute pain.

In 2008, Dr. Birgit Kraft led a small study of cannabis for acute inflammatory pain. Kraft used a double-blind, crossover protocol on 18 healthy female volunteers, evoking pain in several ways and treating it orally with a cannabis extract. It did nothing to reduce acute pain and may have increased it in some subjects.

"The surprising result of our study was the absence of any kind of analgesic activity of THC-standardized cannabis extract on experimentally induced pain using well-established human model procedures,” Kraft said in an interview with Science Daily. “Our results also seem to support the impression that high doses of cannabinoids may even cause increased sensitivity in certain pain conditions.”

A similar study with a more limited scope was performed in 2007 using smoked cannabis. In a randomized, double-blind, placebo-controlled, crossover study with 15 healthy volunteers, researchers tested sensitivity to capsaicin-induced pain. They concluded that there was a "window of modest analgesia for smoked cannabis, with lower doses decreasing pain and higher doses increasing pain.”

In other words, the best cannabis could muster was a mild benefit if a person could manage to hit a sweet spot between too little and too much.

A clinical study in 2006 on cannabis for post-surgical pain did not go so well. Researchers in Berlin used Cannador (a cannabis plant extract) on patients after surgery. None of the patients was able to achieve sufficient pain relief at any dose of Cannador. Several experienced significant side effects, including sedation and nausea. Importantly, the study had to be halted because of a severe adverse event in one patient.

And a 2018 study on “the good, the bad, and the ugly” about medical cannabis came to this conclusion: “Cannabinoids appear to be most effective in controlling neuropathic pain, allodynia, medication-rebound headache, and chronic noncancer pain, but do not seem to offer any advantage over nonopioid analgesics for acute pain.”

There is thus little evidence to suggest that cannabis may be useful for acute, short-lived pain. Instead, the available research points to nontrivial risks, including the possibility of increased pain and adverse reactions.

Better Options Available

Moreover, there are a wide variety of options for treating acute pain, from ibuprofen and other NSAIDs to acetaminophen, topical analgesics, lidocaine and other local anesthetics, and ultrasound therapy. It is more than a bit puzzling that Colorado would be seeking to replace opioids with cannabis when so many well-established options are readily available for acute pain.

For instance, the Journal of the American Dental Association published an analysis of the benefits and risks of analgesic medications in the management of acute dental pain. Results showed that ibuprofen plus acetaminophen offered the best outcome, with acetaminophen with oxycodone and diclofenac, ketoprofen, and difunisal also giving good results. The article concludes that the risks of opioid analgesics, in particular for children and adolescents, can be minimized by medically appropriate use of NSAIDs and acetaminophen.

Furthermore, cannabis does have side effects and risks. Some people do not tolerate it well, and cannabis use disorder reportedly develops in 9% or more of people who use it. Even CBD oil, arguably the safest form of cannabis, has side effects that include fatigue, diarrhea, and possible effects on liver enzymes.

Untreated or undertreated pain has significant clinical consequences, from impeding appropriate diagnostic testing and evaluation to impacting follow-up care and recovery. There are already reliable and effective options for acute and short-term pain management, with fewer risks and side effects than cannabis, few issues with misuse or abuse, and no legal conflicts between federal and state law.

Cannabis has important medical benefits, from controlling chemotherapy-induced nausea and reducing seizures in childhood epilepsy to helping with some chronic pain conditions. But the available evidence does not support cannabis for the management of short-lived acute pain.

Roger Chriss lives with Ehlers Danlos syndrome and is a proud member of the Ehlers-Danlos Society. Roger is a technical consultant in Washington state, where he specializes in mathematics and research.

The information in this column should not be considered as professional medical advice, diagnosis or treatment. It is for informational purposes only and represents the author’s opinions alone. It does not inherently express or reflect the views, opinions and/or positions of Pain News Network.