Marijuana is increasingly being prescribed and used for a variety of medical reasons, including pain relief. But its use is controversial. In the United States it continues to be illegal under federal law. Despite this fact, over half the states in the U.S. have legalized it. Many tout its ability to ease certain of types of chronic pain, especially resulting from nerve damage and inflammation. As a result, medical marijuana is becoming a popular alternative to traditional pain-relieving medications, including opioids.
Today, chronic pain affects more people than cancer, heart disease and diabetes, combined. Chronic pain is the most common cause of long-term disability in the United States and visits to a healthcare provider. Most marijuana-based products do not have approval from the United States Food and Drug Administration (FDA), and there’s no question more evidence is necessary to confirm their safety and effectiveness.
Marijuana contains compounds that may relieve pain, nausea, and other symptoms. Cannabis is the scientific name for the marijuana plant. Researchers prefer to use “cannabis” instead of “marijuana” because marijuana is associated with recreational use. Cannabis Sativa, the Latin name for marijuana, is an herb that has been used for thousands of years to treat many different symptoms. It’s also one of the 50 fundamental herbs used in traditional Chinese medicine (an alternative therapy).
The components of marijuana that most studies focus on for pain relief are cannabidiol (CBD) and tetrahydrocannabinol (THC). THC resembles the cannabinoid chemicals that occur naturally in the body. When people ingest or inhale THC, it stimulates the brain’s cannabinoid receptors. This activates the brain’s reward system and reduces pain levels. THC is a psychoactive compound as it binds to cannabinoid receptors and produces an elevated state of mind, known as a high. CBD does not cause a high, although it does appear to interact with pain receptors in the brain to exert pain-relieving and anti-inflammatory effects.
Anecdotal evidence suggests that marijuana or its compounds may help relieve some types of pain. There are distinct types or strains of available, and each may have slightly different effects. Unfortunately, there is limited research available on the use of specific marijuana strains for pain and other symptoms. As a result, strain-specific recommendations are not medically proven. This is mostly because of the conflicting laws that have legalized marijuana in a majority of states but maintained it illegal federally. Adds Angela Bryan, PhD, professor of psychology and neuroscience at the University of Colorado in Boulder: “The evidence we have thus far suggests that cannabis is moderately effective for pain relief.” Due to convoluted laws, most studies haven’t been able to compare marijuana with other ways to relieve pain.
Why the lack of evidence from research in the U.S.?
Although medical marijuana in some form is legal in 30 states and Washington, D.C., it’s still illegal on the federal level. It’s classified as a Schedule I drug – putting it in the same category as other drugs of “high potential for abuse” that have ”no currently accepted medical use,” such as heroin and LSD.
That means federal rules put limits on what researchers can do. “In the state of Colorado, [which allows medical and adult private use], I can go to any dispensary and buy whatever I want to treat whatever I want,” says Bryan, who’s also co-director of the CU Change Lab, which explores health and risk behavior. “You would think that means researchers can, too. The problem is, researchers are in a federal institution [at the University of Colorado]. If we do anything in violation of federal law, we could have all federal funding withdrawn.”
Bryan’s team has grants for four research studies on marijuana, including one on lower back pain. Participants come to the university for their initial assessment, but then must go to the dispensary on their own to buy the marijuana. Declassifying marijuana as a Schedule I drug would make her research easier, Bryan says, or at least as easy as alcohol research.”If I want to do a study on alcohol, I bring someone in, give them wine, get blood samples, and see what happens when they use alcohol.” She could use marijuana supplied by the government. (The Drug Enforcement Administration (DEA) issued a license to the University of Mississippi to cultivate marijuana for research.) But the marijuana from dispensaries is different and more potent than that supplied by the National Institute on Drug Abuse farm, so it wouldn’t be the same.
Looking at data from 1999 on, reviewing more than 10,000 scientific studies, only seven were directly related to pain relief. One of the seven looked at data from 28 studies. Donald Abrams, MD, a professor of clinical medicine at the University of California, San Francisco, helped review research on marijuana for a 2017 report from the U.S. National Academies of Sciences, Engineering, and Medicine. He says the evidence on marijuana and pain is strongest for helping nerve pain (neuropathy) and cancer-related pain. They also concluded that certain oral cannabinoids improved muscle spasms in patients with multiple sclerosis. Cannabinoids are one of more than 60 chemicals in the cannabis plant. Abrams says it makes sense that marijuana may help relieve pain because the body has cannabinoid receptors, or places where the chemical attaches to cells.
The administration of the THC in marijuana is actually at the center of much of the controversy over its use. Until recently, medical marijuana had to be smoked in order for people to feel any benefit —and because people were smoking it, it was controversial. But more recently, ingesting marijuana has become safer through the development of inhalers which vaporize the herb and allow the THC to be breathed in. Marijuana can also be swallowed through the use of capsules, and it’s effective if eaten as an ingredient in brownies, cookies, cakes or other forms of sweets.
Will marijuana replace opioids?
Some research suggests that marijuana could take the place of opioids. Two recent studies found that states with medical marijuana laws or legalized recreational use may have a decline in opioid prescriptions.
In another study, researchers polled nearly 3,000 medical marijuana patients, including about a third who said they had used opioid pain medicines in the past 6 months. Most said marijuana provided relief equal to their other medications, but without the side effects. While 97% said they were able to lower the amount of opioids they took if they also took marijuana, 81% said that taking marijuana alone was more effective than using both marijuana and opioids.
Although the medicinal use of marijuana for chronic pain looks promising, far more research is required to determine which strains, dosages, and methods of delivery work best. Unfortunately the legal issues between state and federal laws continue to hinder a potentially valuable contender from ever finding its rightful place as a treatment alternative.
Currently, the U.S. Food and Drug Administration (FDA) doesn’t recognize marijuana for any medical condition. And anyone requiring a federal license would be considered an illegal user. There is a wealth of information available, but not all of it is objective or accurate. Be sure any of the websites you review follow the guidelines for credible, reliable health information online. Among the most important guidelines is to find the most current information. The research, laws, and use of medical marijuana change frequently. For now, make sure you speak to a knowledgeable provider, use a reliable dispensary and clarify any and all legal issues before choosing this option.
Next week I’ll discuss in more detail CBD (cannabidiol). This derivative has shown promising results in significantly suppressing chronic inflammation and neuropathic pain without the high of THC- laden cannabis.