​Canadian Researchers Establish Scientific Basis For Medical Use Of Cannabis

There’s now more scientific evidence for what many patients have known for awhile: Smoking marijuana can ease chronic neuropathic pain and help patients sleep better, according to a team of researchers in Montreal.

The new study, published Monday in the Canadian Medical Association Journal , found that pain intensity among patients decreased with higher-potency marijuana, reports Caroline Alphonso of. The study represents an important scientific attempt to determine the medicinal benefits of cannabis.

“A single inhalation of 25 mg of 9.4 percent tetrahydrocannabinol herbal cannabis three times daily for five days reduced the intensity of pain, improved sleep and was well tolerated,” the study concludes. “Further long-term safety and efficacy studies are indicated.”

​”We’re not saying that this is the final solution for chronic pain management,” said lead the study’s lead author, Mark Ware, director of clinical research at the Alan Edwards Pain Management Unit of McGill University Health Centre.

“All that this does is open the door to the cannabinoid being another tool in the toolbox in treating chronic pain,” Dr. Ware said.

Patients suffering from neuropathic pain often use opioid pain medication, antidepressants and local anesthetics, but all of those drugs have limitations, and the side effects of these substances can rival the conditions they are supposed to treat. Unlike “normal” pain, which results from stimulation of pain receptors in the body, neuropathic pain results from damage to or dysfunction of the central or peripheral nervous system, reports Deborah Mitchell at EmaxHealth

But many politicians and medical personnel have been reluctant to advocate medical marijuana because, even though patients champion its use, there have been calls for more scientific studies.

Twenty-one adults with post-traumatic or post-surgical chronic pain took part in the study. They randomly received marijuana at three different strengths: with a tetrahydrocannabinol (THC) content of 2.5 percent, 6 percent and 9.4 percent, and a placebo. THC is one of the main active ingredients in the cannabis plant.

Extremely Small Doses Used

Participants inhaled a single 25-milligram dose through a pipe three times daily for the first five days in each cycle, followed by a nine-day period without marijuana. They continued this for two months, rotating through all three potencies of THC plus the placebo.

The scientists measured pain intensity using a standard scale, with patients reporting the highest-strength cannabis was the most effective at reducing the pain and allowing them to sleep.

Patients reported the pain reduction was “modest,” less than one point on an 11-point scale for the strongest marijuana, reports Reuters . Patients reported no overall difference in their mood or “qualify of life.”

MedPage Today. The most potent dose used reduced average daily pain scores by 0.7 points on an 11-point scale (5.4 versus 6.1 with placebo, 95 percent confidence interval for difference 0.02 to 1.4), according to Dr. Ware and colleagues, reports Crystal Phend at

Almost certainly, one reason the patients reported only “modest” pain relief with cannabis was that they were allowed only a single hit, three times a day, as part of the study. Patients rarely got high on the single hit they took through a pipe.

The fact that relief was experienced, even with such tiny doses, speaks to the effectiveness of cannabis therapy in combating pain.

None of the analgesic doses got plasma levels even halfway to the typical level seen among recreational users, according to the researchers.

So one hopes that the next time marijuana’s effect on pain is studied, they will at least use adequate dosages.

“Noteworthy” Finding: Marijuana Improves Patients’ Sleep

​But the finding that marijuana may actually help improve patients’ sleep is “particularly noteworthy,” according to Dr. Andrea Hohmann, who studies marijuana and pain at the University of Georgia and was not involved in the current study.

“A lot of the treatments that are used for neuropathic pain… might also be associated with disruptions in sleep,” Dr. Hohmann said.

Researchers admitted the study doesn’t address questions about the long-term effectiveness of cannabis therapy. Some patients also reported “adverse effects” such as dizziness, numbness or a burning sensation in areas of neuropathic pain.

More research on marijuana’s effectiveness in reducing pain will be based on this study, according to Dr. Ware.

“As a cannabis user, it can be really hard to get people to take you seriously,” said Amy Brown, 28, a Toronto woman who wasn’t a subject in the study, but uses marijuana to relieve chronic pain and swelling in her wrist, which was injured in a car crash five years ago.

“To me, this study is vindication,” Brown said.

Brown said cannabis is more effective than chemical painkillers, which have unpleasant side effects. “I wasn’t me anymore, I was a drone, I was robot-like,” Brown said of conventional painkillers. “[When I started cannabis], I made a complete 180. I know what’s going on now, I have a clear head.”

The Canadian government has authorized almost 5,000 people to possess dried marijuana, and 3,500 hold personal use cultivation licenses, according to Health Canada. A doctor’s authorization is required before a medical marijuana license is issued.

Several court judgments forced Health Canada to get into the marijuana business a few years ago, so that patients wouldn’t be forced to rely on the black market for their supplies.

Despite its legalization for medical use and Health Canada’s regulations, many in the medical community are still not open to the use of marijuana to relieve pain, according to Dr. Ware.

“There’s a lot of resistance from physicians, and in fact some of the policy-makers, that there isn’t much evidence to support thi

s,” Dr. Ware said. I know some of the colleges and the CMA want to see evidence behind these claims before they will consider supporting or endorsing the regulations.”

“[This study] should provide some support to the fact that there is evidence now out there to support these claims,” Dr. Ware said.

The study adds to three previous investigations of smoked cannabis in coping with neuropathic pain, two of which involved patients with HIV, according to Henry McQuay, professor at Balliol College at the University of Oxford.

Prof. McQuay noted, however, that the participant size of the study was small, the trial was short and it remains to be seen if marijuana can yield greater analgesia with fewer adverse effects than conventional drugs.

“The current trial adds to the trickle of evidence that cannabis may help some of the patients who are struggling at present,” Prof. McQuay wrote in an accompanying commentary to the study.

“If medical cannabis is not available where a patient lives, then obtaining it will take the patient outside of the law, often for the first time in his or her life,” Prof. McQuay wrote. “Good evidence would at least buttress that decision.”