Although the federal government still classifies marijuana as an illegal drug with high potential for dependency and little medical value, medical marijuana is now legal in 29 states and the District of Columbia, and more states appear poised to legalize it in upcoming election cycles.

The increased use of marijuana for medical purposes has caused a proliferation in the claims of its benefits. It seems like every week there’s another news item touting it as a treatment for just about every imaginable ailment, including epilepsy, insomnia, glaucoma, anxiety, nausea and vomiting.

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And although it does appear to have legitimate uses in some cases, can it benefit people who suffer from rheumatoid arthritis?

The simple answer is that the jury is still out.

“There haven’t been any well-conducted studies on medical marijuana and RA,” says Dr. Bharat Kumar, an immunologist specializing in rheumatology and allergies in Iowa City, Iowa. According to Kumar, the few studies that have been done are “small and inadequately designed reviews. The data are just not out there, so there’s no way to say one way or another,” he says.

Dr. Arundathi Jayatilleke, a rheumatologist and assistant professor of medicine at Drexel University College of Medicine in Philadelphia, agrees. “There has been some research on the use of cannabinoids — the active agents in marijuana — in arthritis, but it has been limited,” she says. “There have only been a handful of published trials, and the published research on RA in particular is even slimmer.”

One of the potential benefits of medical marijuana may be as a treatment for chronic pain, which is one of the most common side effects of RA.

“In RA specifically, a study published several years ago [indicated that the] use of cannabis-based medications does seem to show a small benefit in pain relief compared to a placebo,” Jayatilleke notes. “The study was small, and the benefits were also small, though measurable.”

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“Of the RA patients I see, few of them discuss use of marijuana as a major part of their symptom control,” Jayatilleke says. “However, those who do [admit to using marijuana] find it helps with some of the muscle pains and achiness in their joints. Anecdotally, it has not offered enough relief to change the other RA-targeted treatments that they take, although it has allowed some patients to take fewer pain relievers overall,” she adds.

“One of the limitations of the study is that it does not tell us anything about cannabinoids and the inflammation in RA,” Jayatilleke notes.

“Pain is obviously a major part of RA and other rheumatologic conditions, and anything that can safely reduce people’s pain and improve function without exposing them to other side effects is worth studying and considering,” she says. “However, a major factor in the pain related to RA is inflammation, and I have not yet seen anything that proves medical marijuana can alleviate inflammation in RA. Until we study this, I would consider medical marijuana more of an experimental treatment for chronic pain rather than for RA, because as we know well, controlling pain in RA, while an important goal, is not enough to prevent inflammation from causing damage to joints.”

Medical marijuana itself is not necessarily without its own side effects.

“Some of my patients who admit to using it have experienced cyclic vomiting syndrome,” notes Kumar, a clinical assistant professor of medicine in the Department of Internal Medicine at the University of Iowa Hospitals and Clinics. Studies have shown that cyclic vomiting syndrome is a not-infrequent side effect of marijuana use, and the incidence appears to be increasing as more people take up the drug.

And it may cause other problems as well.

“I did see someone in the hospital with vasculitis that we believe was due to marijuana use, although it’s difficult to link one to the other,” Kumar says. According to the Mayo Clinic, vasculitis is an inflammation of the blood vessels that can result in changes in the blood vessel walls that can restrict blood flow, resulting in organ and tissue damage.

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An additional unknown is the most effective dose of the drug. And because it is unregulated, it’s impossible to know just how much marijuana actually enters a person’s system, Kumar notes. “We also don’t know what else is in it,” he says.

Until more research is done on medical marijuana and RA, both Kumar and Jayatilleke are hesitant to recommend its use.

“I tell my patients that I can’t vouch one way or another because there’s no good evidence,” Kumar says. “And I always advise them to be aware of the laws.”

“I am a little hesitant to wholeheartedly support medical marijuana for treatment of RA,” Jayatilleke likewise cautions. “I look forward to future studies which may look at these questions in more depth.”

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More Research Needed Before Medical Marijuana Can Be Recommended for Rheumatoid Arthritis originally appeared on usnews.com