By Pat Anson, PNN Editor

More than 90% of the medical cannabis products advertised in the U.S. contain more tetrahydrocannabinol (THC) than is recommended for chronic pain relief, according to a large new study published in the journal PLOS ONE.

THC is the psychoactive ingredient in marijuana that makes people “high.” Previous studies have shown that medical cannabis containing about 5% THC is effective for treating neuropathic pain. But researchers at Wake Forest University found that many cannabis products sold at dispensaries contain nearly four times as much THC, similar to the amount found in recreational cannabis.

"We know that high-potency products should not have a place in the medical realm because of the high risk of developing cannabis-use disorders, which are related to exposure to high THC-content products," said lead author Alfonso Edgar Romero-Sandoval, MD, associate professor of anesthesiology at Wake Forest School of Medicine.

Romero-Sandoval and his colleagues found that over 8,500 medical cannabis products advertised online contain an average THC concentration of 19.2% -- similar to the average 21.5% THC in recreational cannabis. At least one medical cannabis product contained 35% THC.

Ironically, lower concentrations of cannabinoids (CBD) – the compound in marijuana most often associated with pain relief – were found in high THC cannabis.

“These stated concentrations seem unsuitable for medicinal purposes, particularly for patients with chronic neuropathic pain. Therefore, this information could induce the misconception that high potency cannabis is safe to treat pain,” researchers reported.

“This data is consistent with reports in which THC and CBD in products from legal dispensaries or in nationwide products from the illegal market were actually measured, which indicates that patients consuming these products may be at risk of acute intoxication or long-term side effects.”

Medical cannabis is legal in 33 U.S. states and in Washington, DC. The cannabis products analyzed in the Wake Forest study were advertised by 653 legal dispensaries in California, Colorado, Maine, Massachusetts, New Hampshire, New Mexico, Rhode Island, Vermont and Washington.

Most had THC content well above 15 percent, with Maine reporting the least (70%) and Colorado having the most (91%).

Researchers say between 60% and 80% of people who use medical marijuana use it for pain relief. High concentrations of THC put them at greater risk of intoxication, dependency and tolerance — which means higher and higher concentrations might be needed to get the same level of pain relief.

"It can become a vicious cycle," Romero-Sandoval said. "Better regulation of the potency of medical marijuana products is critical. The FDA regulates the level of over-the-counter pain medications such as ibuprofen that have dose-specific side effects, so why don't we have policies and regulations for cannabis, something that is far more dangerous?"

A recent study published in the journal Cannabis and Cannabinoid Research found that cannabis products often come with misleading labels and marketing claims.

“Widespread mislabeling of hemp and cannabis products has been documented by both independent researchers and the FDA and other organizations. Underlabeling and overlabeling of both CBD and THC content have been reported,” the authors found.

“The actual contents of available products can vary considerably from what are disclosed on the label; sometimes no CBD is present at all. Inadequate label information also poses risks of unintended, unwitting, or overconsumption of THC, the primary intoxicating compound in cannabis, as well as potentially harmful contaminants.”