Some orally ingested marijuana products can provide short-term relief of chronic pain, according to one of the largest-ever reviews of studies on their use for this purpose. Products with a high ratio of tetrahydrocannabinol (THC) to cannabidiol (CBD) seem to offer the most dramatic pain reduction. The relief often comes with side effects including “feeling high” and drowsiness, reports New Scientist.
The most common reported use of medicinal Cannabis in the US is for pain control. As such, weed is a welcome alternative to much more dangerous opioids. More than 20 per cent of adults in the US live with chronic pain, according to the Centers for Disease Control and Prevention.
Several medical studies have suggested that Cannabis can help alleviate pain. But can these products could specifically reduce chronic pain? “Chronic pain” persists for three months or more.
Would Cannabis For Chronic Pain Have Similar Benefits To Opioids?
Additionally, the effect of the ratio of THC to CBD impacted efficacy, Marian McDonagh at Oregon Health & Science University and her colleagues scoured previous research.
“We wanted to know, would cannabis for treating chronic pain have any kind of similar benefits [to opioids]? And of course, we really wanted to look deep into the adverse side effects side, particularly the more serious ones,” McDonagh said.
The scientists looked at more than 3000 studies before identifying 25 that met their strict criteria. Studies had to span at least four weeks and include people with different kinds of pain. These included back pain, chronic headaches and diabetic neuropathy, which causes burning and tingling.
Of those 25 studies, 18 compared marijuana products against placebos. These included 18 clinical trials involving 1,740 people and seven observational studies that included more than 13,000 participants.
None of the products studied are for sale at adult-use Cannabis dispensaries. Instead, they were the pharmaceutical THC products dronabinol and nabilone.
The Annals of Internal Medicine published the review on Monday, reports KGW. It notes the relatively limited amount of scientific research conducted on marijuana products. The available evidence for the benefits of marijuana is “surprisingly thin,” OHSU noted in a news release.
“In general, the limited amount of evidence surprised all of us,” said Dr. McDonagh, lead author. “With so much buzz around cannabis-related products, and the easy availability of recreational and medical marijuana in many states, consumers and patients might assume there would be more evidence about the benefits and side effects.”
The researchers found very little scientifically valid research into most marijuana products, McDonagh said. And the few studies available weren’t designed to answer questions about treating chronic pain.
These Aren’t Dispensary Products
That leaves unexplored many other potential uses for medical pot, including for muscle pain, pinched nerves and other forms of chronic pain, said McDonagh. The lead researcher is professor of medical informatics and clinical epidemiology with the Oregon Health & Science University School of Medicine.
“While there are a lot of people with neuropathic pain, this would not include people with, say, low back pain,” McDonagh said. ”There’s a lot less evidence for those kinds of conditions.”
“The products that we have better evidence on are just not the products we’re talking about in a typical dispensary in one of the U.S. states that allows medical marijuana,” McDonagh said.
The best evidence exists, McDonagh said, for efficacy of FDA-approved drugs dronabinol and nabilone. But that’s likely because the funding for such studies comes from Big Pharma, which is way more interested in selling pharmaceuticals than herbs. (That’s us talking, and not Dr. McDonagh, to be clear.) Those pharmaceuticals also came with significant side effects, including dizziness and sedation, McDonagh said.
High THC, That’s The Ticket
As medical pot has become more widely accepted, so has the notion that THC or CBD products can help treat chronic pain. This new analysis, sponsored by the U.S. Agency for Healthcare Research and Quality, was intended to shed light on the subject.
The researchers then sorted the studies by the type of product being tested — containing high, low or comparable ratios of THC to CBD.
Six randomized controlled studies showed that the high-THC drugs dronabinol and nabilone demonstrated statistically valid benefits for easing neuropathic pain, researchers concluded.
Neuropathic Pain Experienced Greatest Benefits
Participants using products containing at least 98% THC reported a roughly 30 per cent reduction in pain symptoms. There was no significant improvement for patients who consumed products with lower amounts of THC and higher amounts of CBD.
Interestingly, studies have also shown THC-rich Cannabis is more effective than CBD for treating nausea.
“There is so much noise out there about CBD really being able to treat pain,” said McDonagh. “This might help down the road to clarify whether that’s true or not. Right now, there’s just not enough evidence.”
The people that experienced the greatest benefits were those with neuropathic pain – the kind of nerve pain that usually causes tingling and burning sensations.
OHSU intends the document to be a “living review” that will be updated regularly, according to the press release. The university will share the information on a new web-based tool. That’s intendeded to help doctors and researchers evaluate the latest evidence about the effectiveness of medical marijuana.