Can medical marijuana help rheumatoid arthritis?It remains controversial — and thus under studied — in part because it is the most commonly abused illicit drug in the U.S
Steve is a horticulturist of sorts. He raises orchids, Japanese maples, and other plants at his southern Rhode Island home. Tending the plants helps ease his rheumatoid arthritis (RA) pain, he says. But the garden offers more than Zen; he grows one plant — marijuana — specifically to relieve RA pain and discomfort.
"If my pain is at a 10, it will take it down to a 6 or 6.5," he says. "I'm an old-man weight lifter. After I smoke I am able to work my shoulders and arms to keep my joints healthy. It gives me the desire and ability to get through a workout."
Steve has had permission to grow marijuana for medicinal purposes since 2006. He smokes it and cooks it in butter (for baking) and makes THC-containing solutions called tinctures (which can be added to foods and drinks) for himself and five other patients with various medical conditions. His home state is 1 of 16, along with the District of Columbia, where marijuana is permitted for medicinal use.
Cannabis may be useful for people with RA and other chronic pain conditions because it can alleviate pain, reduce inflammation, and promote sleep. But unlike other pain-causing conditions, such as osteoarthritis, RA is associated with a higher risk of lung problems and heart attacks. (RA is an autoimmune condition that attacks the joints and causes multiple health problems.)
It's not clear if smoking marijuana is a relatively safe pain reliever for people with RA, or if it could increase the risk of RA-associated conditions. And if cannabis is safe, it's still debatable whether it's safer to take it as a pill or mouth spray rather than smoking it. Smoking marijuana raises the heart rate and one study found that heart-attack risk rises fivefold in the hour after lighting up, according to the National Institute on Drug Abuse.
Medical marijuana remains controversial — and thus under studied — in part because it is the most commonly abused illicit drug in the U.S.
How marijuana works
There are hundreds of chemicals in marijuana, but the best known is delta-9-tetrahydrocannabinol, or THC. THC is what produces the high that comes with smoking or eating products made from marijuana.
But THC also binds with receptors in the brain that produce an analgesic affect. It may also reduce anxiety experienced by some people dealing with chronic pain.
Marijuana is typically smoked, which produces the most rapid delivery into the bloodstream, says Kathryn Cunningham, PhD, director of the Center for Addiction Research at the University of Texas Medical Branch, in Galveston.
It can also be taken through vaporization (heated into a mist and inhaled), and in edible products, such as baked goods and tinctures, which take longer to have an effect because they have to be broken down in the stomach, Cunningham says.
There are also drugs such as Marinol (dronabinol) and Cesamet (nabilone), which are synthetic versions of THC in pill form that are available by prescription for AIDS patients and cancer patients undergoing chemotherapy, and a newer product called Sativex, a mouth spray with THC and cannabidiol. Sativex is not yet available in the United States, but is used in Canada and Europe for pain relief in people with cancer and multiple sclerosis.
Marijuana is illegal on the federal level, but medicinal marijuana is permitted in some states, including Alaska, Arizona, California, Colorado, Delaware, Hawaii, Maine, Michigan, Montana, Nevada, New Jersey, New Mexico, Oregon, Rhode Island, Vermont, and Washington. Each state has its own guidelines including conditions it can be used for and possession limits (which range from 1 ounce to 24 ounces). Marijuana can be purchased through dispensaries, but most states also allow people to grow the product.
Research is limited
Medicinal marijuana isn't regulated by the Food and Drug Administration, and there aren't large-scale studies of its safety and efficacy for chronic pain conditions. (It doesn't help that there are few manufacturers to fund research.) But there have been some small-scale studies looking at its use.
A 2006 study in Rheumatology looked at 58 RA patients over a five-week period. They were split into two groupsone taking Sativex and the other a placebo. The group on Sativex had improvements in "morning pain on movement" and sleep quality compared to placebo users. (The study was funded by GW Pharmaceuticals, which makes Sativex.)
"This is a good example of how to answer the question with scientifically sound experiments," Cunningham says, adding that larger studies are needed. "We don't know how the drug affects the disease process, but it does seem to have a positive analgesic effect on RA."
Doctors at the University of Toronto and Dalhousie University in Halifax reviewed 18 clinical trials that included 766 people between 2003 and 2010. The trials studied the use of cannabis — either smoked or in THC-based prescription products — as a medical therapy for non-cancer-related pain, most often neuropathic pain (chronic pain that is usually due to nerve damage).
Fifteen of the trials found that it worked better than a placebo for pain relief and four trials found that it improved patients' sleep. A majority of the studies found that side effects like sedation, dry mouth, dizziness, and disturbed concentration were mild enough that people did not drop out of the studies.
However, the analysis included only one study of RA patients — the same 2006 Sativex study — so it could not determine if the long-term use of smoked marijuana was associated with a higher risk of heart or lung complications.