Medicinal Cannabis on Pain and Quality of Life Outcomes in Chronic Pain

Jerusalem, Israel: The daily, long-term use of cannabis is associated with improved analgesia and reduced opioid use in patients with treatment-resistant chronic pain conditions, according to clinical trial data reported online ahead of print in The Clinical Journal of Pain.

Investigators with Hebrew University in Israel evaluated the use of cannabis on pain in a cohort of 176 patients, each of whom had been previously unresponsive to all conventional pain medications. Subjects inhaled THC-dominant cannabis daily (up to 20 grams per month) for a period of at least six months.

A majority of participants (66 percent) experienced improvement in their pain symptom scores after cannabis therapy, and most reported "robust" improvements in their quality of life. Subjects' overall consumption of opioid drugs declined 44 percent by the end of the trial, and a significant percentage of participants discontinued opioid therapy altogether over the course of the study.

Authors concluded, "In summary, this long-term prospective cohort suggests that cannabis treatment in a mixed group of patients with treatment-resistant chronic pain may result in improved pain, sleep and quality of life outcomes, as well as reduced opioid use."

The Israeli results are similar to those reported in a 2015 Canadian trial which concluded that chronic pain patients who use herbal cannabis daily for one-year experienced reduced discomfort and increased quality of life compared to controls, and did not possess an increased risk of serious side effects.

Separate data published in 2014 in The Journal of the American Medical Association determined that states with medical marijuana laws experience far fewer opiate-related deaths than do states that prohibit the plant. Investigators from the RAND Corporation reported similar findings in 2015, concluding, "States permitting medical marijuana dispensaries experience a relative decrease in both opioid addictions and opioid overdose deaths compared to states that do not." Clinical data published in 2011 in the journal Clinical Pharmacology & Therapeutics previously reported that the administration of vaporized cannabis "safely augments the analgesic effect of opioids."

A scientific review published earlier this year assessing the clinical use of cannabinoids for pain in over 1,300 subjects concluded, "Overall, the recent literature supports the idea that currently available cannabinoids are modestly effective analgesics that provide a safe, reasonable therapeutic option for managing chronic non-cancer-related pain and possibly cancer-related pain."

Full text of the study, "The effect of medicinal cannabis on pain and quality of life outcomes in chronic pain: A prospective open-label study," appears in The Clinical Journal of Pain.  See the United States Government's  National Center for Biotechnology Information website for the abstract

Marijuana Relieves Chronic Pain, Research Shows

Three puffs a day of cannabis, better known as marijuana, helps people with chronic nerve pain due to injury or surgery feel less pain and sleep better, a Canadian team has found.

''It's been known anecdotally," says researcher Mark Ware, MD, assistant professor of anesthesia and family medicine at McGill University in Montreal. "About 10% to 15% of patients attending a chronic pain clinic use cannabis as part of their pain [control] strategy," he tells WebMD.

But Ware's study is more scientific -- a clinical trial in which his team compared placebo with three different doses of cannabis. The research is published in CMAJ, the Canadian Medical Association Journal.

The new study ''adds to the trickle of evidence that cannabis may help some of the patients who are struggling [with pain] at present," Henry McQuay, DM, an emeritus fellow at Balliol College, Oxford University, England, writes in a commentary accompanying the study.

Marijuana for Pain Relief: Study Details

Ware evaluated 21 men and women, average age 45, who had chronic nerve pain (also called neuropathic pain). A typical example, Ware tells WebMD, is a patient who had knee surgery and during the course of the operation the surgeon may have had no choice but to cut a nerve, leading to chronic pain after the surgery.

Ware's team tried three different potencies of marijuana, with the highest a concentration at 9.4% tetrahydrocannabinol (THC) herbal cannabis. He also tested 2.5% and 6% THC.

''Each person was in the study for two months, and used all four strengths [including placebo]," Ware says. He rotated them through the four strengths in different orders, and they didn't know which they were using.

The cannabis was put into gelatin capsules, then put into the bowl of a pipe. Each person was told to inhale for five seconds while the cannabis was lit, hold the smoke in their lungs for 10 seconds, and then exhale.

They did this single puff three times a day for five days for each of the doses and the placebo. The participants were allowed to continue on their routine pain medications.

After each of the five-day trials, participants rated their pain on a scale of zero to 10, with 10 being the worst.

Read more: Marijuana Relieves Chronic Pain, Research Shows

Marijuana For Chronic Pain Is Safe, Effective

Chronic pain patients who use herbal cannabis daily for one-year report reduced discomfort and increased quality of life compared to controls, and do not experience an increased risk of serious side effects, according to clinical data published online ahead of print in the Journal of Pain.

Researchers at McGill University in Montreal assessed the long-term health of 216 medicinal cannabis users with chronic non-cancer pain who consumed a daily standardized dose (12.5 percent THC) of herbal cannabis compared to 215 controls (chronic pain suffers who did not use cannabis). Subjects in study were approved by Health Canada to legally use medicinal cannabis and consumed, on average, 2.5 grams of herb per day, typically via inhalation or vaporization.

Investigators reported that daily cannabis consumers possessed no greater risk than non-users to experience “serious adverse events.” Specifically, researchers identified no significant adverse changes in consumers’ cognitive skills, pulmonary function, or blood work following one-year of daily cannabis consumption. Medical cannabis consumers did report elevated risk of experiencing “non-serious adverse events” (e.g., cough, dizziness, paranoia) compared to controls; however, authors classified these to be “mild to moderate.”

Pain patients who used cannabis reported a reduced sense of pain compared to controls, as well as reduced anxiety, depression, and fatigue.

“Quality-controlled herbal cannabis, when used by cannabis-experienced patients as part of a monitored treatment program over one year, appears to have a reasonable safety profile,” authors concluded.

The study is one of the first to ever assess the long-term safety and efficacy of medicinal cannabis. A prior health review of patients receiving medical cannabis monthly from the US federal government as part of the Compassionate Investigational New Drug program similarly reported that cannabis possesses therapeutic efficacy and an acceptable side-effect profile.

See full text of the study, “Cannabis for the Management of Pain: Assessment of Safety Study,” online.