Can cannabis replace opioids?

In 1995, the president of the American Pain Society called for pain to be added as a fifth vital sign evaluated and managed by physicians—body temperature, heart rate, respiration, and blood pressure are the original four. Measuring pain subsequently became a widely accepted practice among clinicians. With 20% of adults experiencing chronic pain, prescription opioids soon doubled and Americans began consuming 80% of the global opioid supply.

President Trump officially declared the opioid crisis a “public health emergency” in October 2017. By then, the United States was approaching 50,000 opioid overdose deaths total and nearly 60% of them were due to illicit synthetic opioids such as fentanyl or tramadol. The problem has continued to escalate. Last year, there were more than 80,000 opioid overdose deaths with roughly 90% resulting from highly potent synthetic forms. This crisis is not getting better, and new strategies are needed to solve the problem.

Does legalizing cannabis reduce opioid use?

There are several reasons why legalizing cannabis seems like a promising strategy to combat the ongoing opioid crisis. For one, early population reportsfound that states that legalized medical cannabis saw a reduction in opioid overdose deaths. However, those findings no longer hold when the timeline of analysis is extended to the present day; any benefit that cannabis legalization has on reducing opioid overdose seems to be short lived.States that legalized recreational cannabis saw an initial reduction in opioid-related emergency room visits by 7.6% compared to states that did not legalize cannabis, but this difference was gone within 6 months. It remains possible that cannabis may serve as a substitute for common prescription opioids like oxycodone, codeine, or hydrocodone, but can’t overcome the severity of dependence to more potent illicit opioids like fentanyl or heroin that are being abused at escalating rates.Some studies point to notable reductions in prescription opioid use among patients who also use cannabis, but this benefit disappears in rigorously controlled clinical trials. These clinical trials fail to find consistent results on cannabis co-use with prescription opioids, despite most patients saying that they prefer cannabis over opioids.

How might cannabis replace opioids?

There are currently 15 ongoing clinical trials investigating the ability of cannabis to reduce opioid need. These clinical trials are driven by hard-to-ignore evidence from animal studies that look at the pain-relieving interactions between the endocannabinoid system, which is stimulated by cannabinoids like THC, and the opioid system.Pain experiments in rodents have consistently found that THC reduces the need for opioids. Across seven different studies, THC reduced the effective dose of morphine by 3.5 times. This beneficial effect is supported by three key pieces of evidence:

1. Many cannabinoids, such as THC, stimulate CB1 receptors in the endocannabinoid system, which are found in the same pain-processing brain areas as opioid receptors and may also contribute to pain reduction.
2. CB1 receptors in the body interact with opioid receptors to boost their pain-relieving effect in rodent studies.
3. CB2 receptors, another cannabinoid target, can stimulate the release of the body’s own opioids which activate pain-relieving opioid receptors.

So why is there inconsistency between these ongoing clinical trials and the population studies mentioned above?A direct reason is unclear. Some argue that a sense of control over pain management, as one experiences when they choose to use cannabis, can promote better outcomes. This effect could explain why patients who could choose to co-use cannabis in certain trials, as opposed to randomized clinical trials, reduced their need for opioids.

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