How Can Cannabis Help Treat Chronic Pain?

The study of cannabis is continually evolving and we are constantly gaining a better understanding of why cannabis can be an effective treatment for a variety conditions, particularly chronic pain conditions. Exo-cannabinoids — including synthetic and botanical preparations — act on the body’s endocannabinoid system (ECS). The ECS, which scientists only discovered two decades ago, is one of the body’s most important physiological systems.

Dr. Donald Abrams, a professor and Chief of Hematology & Oncology at San Francisco General Hospital, notes there is a convincing body of evidence showing cannabis “is effective in a number of neuropathic pain syndromes,” and that cannabinoids may not only play a role in symptom management, but also provide preventative benefits.

The endocannabinoid system is responsible for a number of physiological functions related to health, including pain modulation and inflammation. The ECS, through two receptors, CB1 and CB2, help modulate a variety of functions, including:

CB1: Appetite, immune function, muscle control, pain, cognition, and reward

CB2: Immune function, cell proliferation, inflammation, and pain

“I believe that the reason we and all animal species have the complex system of cannabinoid receptors and endocannabinoids is to help us modulate the experience of pain,” notes Dr. Abrams. “It is no wonder, therefore, that the plant cannabinoids also seem to have a significant analgesic activity. We have studied the effectiveness of cannabis in painful nerve damage (neuropathy) as well as in combination with opiates. From my own oncology practice I am impressed that cancer patients are able to decrease their use of narcotic analgesics when adding in cannabis medicines.”

When you ingest cannabis, cannabinoids such as THC and CBD, can act on the endocannabinoid system’s receptors and periphery to provide anti-inflammatory and analgesic effects.

How Effective Are Cannabinoids in Treating Chronic Pain?

Over 200 studies have been conducted evaluating the efficacy of cannabis and cannabinoid-derived formulations to treat chronic pain conditions. One comprehensive systematic study conducted by Harvard professor and addiction psychiatrist, Dr. Kevin Hill, reviewed 28 well-designed studies. Hill evaluated six chronic pain trials of 325 patients; five neuropathic pain trials that included 396 patients; and, 12 multiple sclerosis trials that included 1600 patients. The author concluded, “[The] use of marijuana for chronic pain, neuropathic pain, and spasticity due to multiple sclerosis is supported by high-quality evidence.”

Summary of key findings:

• Six out of six general chronic pain studies demonstrated significant improvement in symptoms.

• Five out of five neuropathic pain studies found a significant improvement in symptoms. (Three out of five studies investigated “smoked” cannabis, while two examined an oral spray preparation).

Canadian researchers came to similar conclusions in their 2011 Review Study of 18 trials, identifying 15 trials that demonstrated efficacy in treating chronic non-cancer pain. Of the 18 studies, 15 investigated neuropathic pain, while five (overlapping studies) examined other types of pain (one in fibromyalgia; one in rheumatoid arthritis; and, one as an adjunct to opioids in patients with mixed chronic pain; and, two in mixed chronic pain).

They noted several trials reported significant improvements in sleep, with no serious side effects. Further, the studies found just a few adverse effects which were mild to moderate and well tolerated.  

Can Cannabis Help Patients Eliminate (Or Reduce) Opioids?

In recent years, North America has been ravaged by an ever-growing epidemic: opioid abuse. Since Purdue Pharma brought OxyContin to the market in the mid 1990s, prescriptions have increased four-fold. Following the increase in prescriptions, rates of heroin addiction and the number of opioid-related overdoses have skyrocketed.
 

“Cannabis can play an important role in pain relief — with or without opiates — and, given the epidemic level of opioid overdoses, clearly more physicians should seriously consider cannabis as part of their patients’ therapeutic protocol. Not to, would be irresponsible, if not unethical.” — Dr. Michael Hart

While the government has (belatedly) tried to solve the epidemic by clamping down on “pill mills,” and revising recommended opioid prescription protocols, the actions have elicited unintended consequences. Many individuals who developed a dependency on prescription narcotics found access to OxyContin more difficult, and turned to heroin for a cheaper, more easily accessible, and more potent “high.” There is incontrovertible evidence that proves opioids are often a gateway to heroin, with four out of five heroin addicts reporting have become opioid addicted starting with prescription narcotics, like Vicodin and OxyContin.

Data from the Centers for Disease Control (CDC) illustrate how dire the situation is:

• Fatal overdoses have increased by 400%: sales and overdoses of prescription opioids quadrupled between 1999 and 2014.

• More than 165,000 people have died in the U.S. from overdoses related to prescription opioids between 1999 and 2014

• At least half of all U.S. opioid overdose deaths involve a prescription opioid.

• More than 14,000 people died from overdoses involving prescription opioids in 2014.

How could medical marijuana help? By providing an efficacious substitute to opioids, or helping patients reduce their opioid intake. The (CDC) argues that the opioid prescribing is fueling the epidemic, so it would be a sensible strategy to encourage physicians to consider cannabis as an alternative (or, adjunct) to opioid-based treatment programs.

According to Dr. Abrams, “In my clinical practice I have seen many patients decrease their dose of narcotics or wean off them altogether with the addition of cannabis to their regimen. Pain relief, with or without opiates, is another area where cannabis may be quite useful.”

Evidence suggests opioids are only effective for acute pain, and many patients find they must progressively increase their dosage to achieve the same effect; within a short period of time, their pain isn’t responsive to opioid treatment. On the other hand, there is evidence that cannabis (or, more specifically, cannabinoids) may act synergistically with opioids, allowing patients to lower dosage of opioids while achieving comparable pain relief.

According to Dr. Abrams, evidence from studies on animal models, suggest, "Cannabinoids appear to be synergistic with opioids in producing analgesia.” Based on preclinical research, Dr. Abrams conducted a small study to investigate cannabis as an opioid potentiator. His team found that vaporized cannabis didn’t affect morphine or oxycodone blood levels, but they observed synergistic pain relief. After the addition of vaporized cannabis, patients realized a 27% decrease in pain. Abrams and his team concluded vaporized cannabis “augments the analgesic effects of opioids without significantly altering plasma opioid levels.”

“We have studied the effectiveness of cannabis in painful nerve damage (neuropathy) as well as in combination with opiates. From my own oncology practice I am impressed that cancer patients are able to decrease their use of narcotic analgesics when adding in cannabis medicines.” — Dr. Donald Abrams, Chief of Hematology & Oncology - San Francisco General Hospital

Other studies support the role of cannabis as part of a strategy to reduce opioid use. A University of Michigan March 2016 Study provided evidence that cannabis may be superior to opioids and provide a valuable harm reduction strategy. Noting that while opioids are commonly used to treat patients with chronic pain, “there is little evidence that they are effective for long term [chronic pain] treatment.

The study, published in the Journal of Pain, provides compelling data that cannabis is effective as an adjunct to therapy:

• Patients Reduce Opioid Intake: Cannabis use was associated with 64% lower opioid use in patients with chronic pain.

• Improved Quality of Life: Cannabis use was associated with better quality of life in patients with chronic pain.

• Fewer Side Effects: Cannabis use was associated with fewer medication side effects and medications used.

• Fewer Fatal Opioid Overdoses: Previous studies reported strong associations between passage of medical cannabis laws and a decrease in opioid overdose statewide.

Dr. Daniel Clauw, one of the study’s researchers and a professor of pain management anesthesiology at the University of Michigan Medical School, commented: "We are learning that the higher the dose of opioids people are taking, the higher the risk of death from overdose. This magnitude of reduction in our study is significant enough to affect an individual's risk of accidental death from overdose."

Case Study: Kevin Ameling, A Real World Success Story

A “real-world” success story comes from Kevin Ameling, a chronic pain patient from Colorado. After getting injured from a fall in 2007, his doctor prescribed him a combination of prescription drugs that included Clonazepam, Tramadol, Lexapro, and OxyContin.

As his chronic pain progressed, Ameling had found the drugs to be less effective, particularly the OxyContin. A resident of Colorado, he became a medical marijuana patient. Cannabis helped him reduce reliance on on prescription drugs, allowing him to cut his dosages significantly:

• Clonazepam: 3 mg to .5mg

• Lexapro: 30 mg to 5 mg

• Tramadol: 300 mg to 75 mg

• OxyContin: Reduced daily intake by more than 50% (and, reports being able to skip doses)

“I was well aware of the dangers associated with benzodiazepines and opioids, and didn’t want to be a statistic. OxyContin became less effective and I didn’t want to up my dosage,” recounts Ameling. “By using cannabis as an adjunct to my therapy, I was able to cut back on all my medications. Most impressively, while reducing my OxyContin intake, it didn’t become less effective, and in fact, I believe cannabis allows OxyContin to be maintain efficacy far longer than typical.  

Ameling noted everyone responds differently, but for him, “low dose edibles work much better than smoking. In fact, smoking seems to worsen my symptoms, while edibles clearly improve them.”