The high prevalence of chronic pain, combined with over-reliance on opioid prescriptions, has led to overuse and a desperate need for solutions. Whether cannabis could play a role in combating chronic pain and the overuse of opioid-derived medications (Oxycontin, morphine, etc.) is a matter of debate.
Recent surveys suggest that a large number of people use cannabis as a treatment for pain and to reduce opiate consumption and cannabis-derived products show at least modest efficacy in treating pain in randomized controlled trials. For example, surveillance studies from countries that have approved the use of Sativex, which is a cannabis-based product, have shown that a combination of Δ9-tetrahydrocannabinol and cannabidiol has low dependence potential, is well tolerated, and is useful to patients.
Given the number of people already using cannabis for pain management and opioid use in state-regulated markets, it is imperative to conduct additional research in these areas, and to disseminate information on how to minimize harm and maximize all the benefits of using cannabinoids to alleviate pain and reduce opioid use.
Opioid abuse is linked to the over-prescription of these drugs by physicians, and recent estimates suggest that 25.3 million American adults suffer from chronic daily pain. Although there are a number of unapproved treatments for neuropathic and somatic pain (e.g., nonsteroidal anti-inflammatory drugs (NSAIDs), tricyclic antidepressants, gabapentin, pregabalin), many of these treatments have demonstrated poor efficacy, adverse side effects, and poor tolerability. In addition, adjunctive therapies such as physical therapy, cognitive-behavioral treatments and acupuncture, which are known to be effective against chronic pain, are not always reimbursed by insurance companies.
Easy access, potential for abuse?
Over the past two decades, opioid prescriptions have increased dramatically. Between 1999 and 2010, the number of opioid prescriptions increased fourfold, while the rate of overdose deaths has increased 200% since 2000. Overdose deaths continue to rise as people who were initially prescribed these drugs have turned to cheaper products available on the street, including heroin and dangerously potent synthetics (i.e. fentanyl and fentanyl derivatives).
Although the reasons for this transition are likely multifactorial, results from qualitative studies suggest that people who previously used prescription opioids switched to illegal forms of opioids because of their cost and ease of access after becoming physically and emotionally dependent. Some estimates suggest that among heroin injectors, 39% report having been "addicted" to prescription opioids before switching to heroin.
In addition to the high risk of overdose, long-term opioid use raises a number of other concerns. For example, there is a clear lack of evidence of the usefulness and safety of their use in the treatment of chronic pain.
An unbalanced risk/benefit ratio
Of the 91.8 million U.S. adults who use prescription opioids for pain relief, 12.5% report misuse. The high rate of misuse may be explained, at least in part, by the tolerance that develops with continued use of these drugs. Continued use is associated with two key processes: tolerance and opioid-induced pain sensitivity (hyperalgesia).
Together, these phenomena can reduce effectiveness in the treatment of chronic pain and contribute to misuse of these products. Similarly, prolonged opioid use has been associated with neuroinflammation and damage to the brain and immune system. Finally, recent evidence suggests that opioid treatment for chronic pain is no more effective than non-opioid medications in reducing pain. Therefore, in many cases, the negative consequences associated with the use of these medications outweigh any benefit to the patient.