Dr. Mark Ware first witnessed the powerful pain relieving effects of marijuana while working at a clinic dedicated to sickle cell anemia research in Jamaica in 1998.
A Rastafarian in his late 70s, with full blown sickle cell disease, had made the trek from his home in the mountains to the Kingston clinic. He was much older than the average life expectancy for someone with the disease and didn’t exhibit any of the tell-tale symptoms, such as severe pain in the chest, hands and joints. Instead, he was fit and spry.
A dumbfounded Ware asked, “What’s your secret?”
The man leaned in and with a penetrating look, said, “You must study the herb, doc.”
“That began a journey and a voyage of discovery that hasn’t stopped today,” says Ware, who grew up in Jamaica and is now a Canadian-based world-renowned expert on cannabis use for pain.
That very afternoon Ware scoured the medical literature for marijuana, pain and sickle cell disease, eventually stumbling upon some animal research showing cannabinoids had analgesic properties. But all the literature noted the need for clinical trials.
That’s one reason the use of marijuana for therapeutic purposes is such a controversial issue: Few clinical trials have evaluated the effects.
Ware had not considered studying pot for pain control. But, why not? Jamaica appeared to the “perfect place.” He was surrounded by people with debilitating pain and limited treatment options. Plus, he didn’t think he’d have difficulty getting hold of marijuana.
However, he didn’t have access to the necessary materials and institutional support to do his research. So he looked elsewhere.
In 1999, Canada approved medical marijuana and announced funding for researching the therapeutic benefits of pot. Ware headed to McGill University to work in a large pain treatment clinic, where patients told him weed helped with pain, sleep, spasticity, mood, appetite and nausea. He began studying the effects of cannabis on neuropathic pain, a chronic condition caused by nerve injury from trauma or surgery.
“We weren’t looking for people to get high,” says Ware, director of clinical research at the Alan Edwards Pain Management Unit at McGill University Health Centre. “We were looking to help them relieve symptoms, and use the smallest amount possible to get symptom control.”
In a landmark 2010 study, 21 participants smoked low doses — one puff three times daily for five days — of cannabis containing different amounts of tetrahydrocannabinol (THC), an active ingredient in marijuana. People were treated over four different periods, with marijuana containing between 0 and 9 per cent THC. They reported less pain and improved sleep after smoking the pot with the highest potency of THC, according to the study called Smoked Cannabis for Chronic Neuropathic Pain: A Randomized Controlled Trial, published in the Canadian Medical Association Journal.
Although more research is needed, there is a lot of data on the therapeutic application of marijuana, says Ware. He is also the executive director of the non-profit Canadian Consortium for the Investigation of Cannabinoids (CCIC), which provides educational material to health professionals so they can have informed discussions about possible medical use of cannabis with patients.
At a conference last year in Washington D.C. Ware spoke of opioids and cannabinoids, which are compounds found in cannabis that have therapeutic effects and bind to cannabinoid receptors in the brain. The big difference is that opioid pain relievers in high doses kill people.
“We have a drug problem, and it’s opioids,” he said at the National Medical Cannabis Unity Conference. “But we also have a pain problem. We have a tremendous amount of pain in our society and it’s a huge burden. It costs us money in treatment, it costs us money in lost productivity and it costs us personal suffering.”
So if we’re looking for new pain control methods, and don’t want to use opioids, we should continue to do more studies on cannabinoids, he said.
“As a primary care practitioner, I can tell you that the hardest thing you can ever do is tell somebody, ‘I’ve got nothing left to offer you,’ when they are in pain,” he told the annual meeting. “That is a devastating thing to tell somebody and it’s even more devastating to have to hear.”
Ware is not advocating that every doctor should prescribe medicinal marijuana or that every patient should try it. But, he calls it “one particular tool in the toolbox that we have to treat patients with chronic pain.”
The Canadian Medical Association, however, argues there is no clinical evidence to justify pot as a treatment and is critical of new medical marijuana regulations that take full effect April 1, which put the onus on doctors to write prescriptions. Asking physicians to prescribe something that hasn’t been rigorously tested, and is available in a wide variety of strains, means they have no information about dosages, benefits or side effects, says the association, calling it akin to asking them to work blindfolded and potentially harm patients.
For Ware, the benefits are clear. He recalls two cases of patients whose pain was so unbearable they were suicidal. In both cases marijuana was a life-saver.
“Cannabis lifted them out of that end-game thought process,” says Ware. “We were able to turn them around and help them see a future where things could be a little more optimistic.”
He understands concerns about long-term effects of pot-smoking on the lungs, risks of addiction and risks of psychosis. But by doing more research we may be able to answer those questions, he says.
Posted at: http://medicalmarijuana.ca/news/0/228
Smoked cannabis for chronic neuropathic pain: a randomized controlled trial
- Mark A. Ware, MBBS,
- Tongtong Wang, PhD,
- Stan Shapiro, PhD,
- Ann Robinson, RN,
- Thierry Ducruet, MSc,
- Thao Huynh, MD,
- Ann Gamsa, PhD,
- Gary J. Bennett, PhD,
- Jean-Paul Collet, MD PhD
+ Author Affiliations
From the Department of Anesthesia (Ware), the Department of Family Medicine (Ware), the Department of Epidemiology, Biostatistics and Occupational Health (Wang, Shapiro), the Department of Medicine (Huynh) and the Alan Edwards Centre for Research on Pain (Gamsa, Bennett), McGill University, Montréal, Que.; Boreal Primum (Robinson, Ducruet), Montréal, Que.; and the Centre for Applied Health Research and Evaluation (Collet), University of British Columbia, Vancouver, BC
- Correspondence to:
Dr. Mark A. Ware, E19.145, Montréal General Hospital, 1650 Cedar Ave., Montréal QC H3G 1A4; firstname.lastname@example.org
Background: Chronic neuropathic pain affects 1%–2% of the adult population and is often refractory to standard pharmacologic treatment. Patients with chronic pain have reported using smoked cannabis to relieve pain, improve sleep and improve mood.
Methods: Adults with post-traumatic or postsurgical neuropathic pain were randomly assigned to receive cannabis at four potencies (0%, 2.5%, 6% and 9.4% tetrahydrocannabinol) over four 14-day periods in a crossover trial. Participants inhaled a single 25-mg dose through a pipe three times daily for the first five days in each cycle, followed by a nine-day washout period. Daily average pain intensity was measured using an 11-point numeric rating scale. We recorded effects on mood, sleep and quality of life, as well as adverse events.
Results: We recruited 23 participants (mean age 45.4 [standard deviation 12.3] years, 12 women [52%]), of whom 21 completed the trial. The average daily pain intensity, measured on the 11-point numeric rating scale, was lower on the prespecified primary contrast of 9.4% v. 0% tetrahydrocannabinol (5.4 v. 6.1, respectively; difference = 0.7, 95% confidence interval [CI] 0.02–1.4). Preparations with intermediate potency yielded intermediate but nonsignificant degrees of relief. Participants receiving 9.4% tetrahydrocannabinol reported improved ability to fall asleep (easier, p = 0.001; faster, p < 0.001; more drowsy, p = 0.003) and improved quality of sleep (less wakefulness, p = 0.01) relative to 0% tetrahydrocannabinol. We found no differences in mood or quality of life. The most common drug-related adverse events during the period when participants received 9.4% tetrahydrocannabinol were headache, dry eyes, burning sensation in areas of neuropathic pain, dizziness, numbness and cough.
Conclusion: A single inhalation of 25 mg of 9.4% tetrahydrocannabinol herbal cannabis three times daily for five days reduced the intensity of pain, improved sleep and was well tolerated. Further long-term safety and efficacy studies are indicated. (International Standard Randomised Controlled Trial Register no. ISRCTN68314063)
Article at: http://www.cmaj.ca/content/182/14/E694.abstract