While physicians are well-aware of the opioid addiction in the U.S., many are still wary about the use of medical marijuana to manage chronic pain, according to Daniel Clauw, MD, of Ann Arbor-based University of Michigan.
In a blog post for University of Michigan Health's Lab Blog, Dr. Clauw, a professor of anesthesiology, psychiatry and rheumatology at the University of Michigan who specializes in chronic pain, says chronic pain affects 100 million Americans and costs $600 billion per year.
While the IOM notes common uses of diagnostic studies and interventions are not backed by evidence-based medicine to manage chronic pain, "the rampant use of opioids to treat chronic pain stands out as the lease defensible and most harmful of our maltreatments," wrote Dr. Clauw.
He argues there is little evidence that opioid narcotics is effective for treating chronic pain, and for every patient who does find them helpful, there are many more who are not helped or even harmed by these drugs. The most blatant example: More than 14,000 Americans died in 2014 from unintentional overdose of prescription opioids. Many others continue taking the pain medication because they enjoy feeling numb or are unaware of other more appropriate therapeutic options.
Meanwhile, many states have taken steps to legalize or decriminalize the use of cannabis for the treatment of chronic pain and other conditions. Medical marijuana laws are now in effect in 25 states and Washington, D.C. But while the public has largely backed the decriminalization or legalization of marijuana, the medical community is generally less enthused.
This is the case for a few reasons, according to Dr. Clauw. "Notwithstanding the legal issues (cannabis is still a Schedule I drug that cannot be prescribed), there are other legitimate issues that preclude acceptance by physicians," he wrote. "Even if we could prescribe cannabis, we have no idea what strength or dose to use, or which route of administration is most effective."
According to Dr. Clauw, both classes of drugs are modestly effective at best, and only work well in a small subset of patients. They function similarly in that they dissociate individuals from the sensation of pain, but do not treat the root cause of pain. "Opioids may be more effective in pain related to peripheral inflammation or damage, and cannabinoids more effective for neuropathic and centralized pain conditions such as fibromyalgia," wrote Dr. Clauw. However, while the benefits of these two types of drugs might be comparable, the risks are not, he said.
Yet physicians favor opioids because of distorted perceptions dating back to the 1960s, which include the belief that opioids are effective for chronic pain of all kinds, while cannabis will lead one to "death, debauchery or hopeless insanity," Dr. Clauw wrote. "We need to adjust our perceptions about these two classes of drugs based on current evidence."
Ultimately, however, "neither opioids nor cannabinoids should be used as first-, second- or third-line therapies for pain, as there are almost always many much more effective and safer drug and nondrug therapies," he wrote. "We can and should do better for our patients."