Dr. Abrams disagrees. “I’m a cancer doctor, not a rheumatologist, but most dispensaries in California, where I live, tell you whether you’re getting indica or sativa, as well as the percent of THC it contains,” he says. “And the bottom line is, marijuana is a very safe drug. When we give patients with chronic pain a prescription for gabapentin [a drug often used as a painkiller], we say, ‘Start with one; try two or three if that doesn’t work.’ It’s the same with medical marijuana: Start low and see how it goes.”

In addition, says Dr. Abrams, “As an oncologist, I see patients who have extreme pain, depression and nausea. I feel comfortable being able to recommend one ‘medication’ – a medication they can even grow themselves, which is very empowering – with few side effects, rather than multiple prescriptions for medications with severe side effects.”

In fact, Dr. Pope’s study found that the most common side effects of oral cannabinoids were drowsiness and confusion, and marijuana is not known to have negative interactions with medications used for RA, OA or most other musculoskeletal or rheumatic diseases. However, says Dr. Fitzcharles, “My research has shown that it is associated with anxiety in individuals with fibromyalgia. And because THC concentrations are so much higher than they used to be even 10 years ago, it is a known cause of acute psychotic episodes in Canadian emergency rooms.”

THC potency now can be greater than 20 percent – 10 times higher than in the 1960s and ’70s, Dr. Silverman adds.

Even so, many medical marijuana users with chronic pain say they don’t experience the “high” recreational users do – which some experts say may be due to complications in nerve signaling. Plus, medical marijuana users can choose specific strains with low concentrations of THC, adds Dr. Abrams.

Bottom Line

Every expert interviewed for this story expressed enthusiasm over research on cannabis and arthritis – and cautioned that the best options for most people are treatments with a proven track record.

“There’s no question that cannabinoids have the potential to have an impact on the disease,” says Dr. Fitzcharles. Even so, she adds, “I think to turn to something with very little evidence – and so much potential to have negative impact – is dangerous.”

Proven, effective treatments are already available for RA, OA and diseases like lupus, says Dr. Pope. But, she says, “We do need better treatments.”

Patients with chronic musculoskeletal pain have an unmet need for pain relief, given that existing medications, especially narcotics, have side effects that include addiction and impairment. Cannabis may come to fill the gap.

For now, however, “Medical marijuana is uncharted territory,” says Dr. Silverman. “So buyer beware.”

Camille Noe Pagán is a contributing editor to Arthritis Today.

For the full article, see the May/June 2013 issue of Arthritis Today.