A 52-year-old brain cancer patient taking a pot concentrate to boost his appetite landed in the ER after taking a dose 35 times stronger than a recreational user might take, said report author Dr. Jeanmarie Perrone, director of toxicology and addiction medicine with the Hospital of the University of Pennsylvania in Philadelphia. Medical marijuana is legal in Pennsylvania.
"What he did is what we see patients do all the time: 'Let's try a little bit. Oh, I'm not sure I got it,'" she said. "It becomes dangerous to measure or absorb or get the right quantity when it is so concentrated."
The patient appeared in the emergency room in a state of extreme delirium, Perrone said.
"He was quite confused. He was acting bizarre," she said. "He had a history of a brain tumor, so of course our first possibilities when evaluating him was he had a complication from his brain tumor."
Tests revealed that wasn't the case, which left doctors scratching their heads.
"It was really in the final moments of admitting him to the hospital where I went to look at the regular medications he takes, and in that bag full of his regular medications there was this syringe," Perrone said.
The syringe contained a 500-milligram dose of liquid THC, the ingredient in marijuana that produces a high, she said.
By comparison, it takes about 10 mg to get a person high recreationally, Perrone said.
The man had taken about two-thirds of the concentrate, doctors learned.
The patient received supportive care and eventually came down from his intoxication, researchers reported.
Mitch Earleywine - an advisory board member for NORML, which favors reform of marijuana laws - said such an overdose of a THC extract is a "terrible idea for anyone."
Dr. Laura Shoemaker, a palliative medicine doctor who works with cancer patients at the Cleveland Clinic, reviewed the study and urged patients to check with their doctor before trying medical marijuana. She noted that patients often turn to medical pot in hopes of relieving suffering that their current treatment is not addressing.
"In the midst of these hopes, patients might not appreciate that the substance they're using might be failing to do that job and potentially causing additional problems," Shoemaker said. Doctors need to know about bothersome symptoms and suffering, she added.
Meanwhile, Perrone said manufacturers and dispensaries need to do a better job of providing dose information and warning patients against taking too much, even if they don't feel the effects immediately. None of these medical pot products from dispensaries are approved by the U.S. Food and Drug Administration.
"Every medication we dispense as an FDA drug has a package insert," she said. "While there's a lot of complicated language, there's obviously some value to some basic dosing instructions."
Perrone said it would be helpful if dispensaries would offer more guidance and if manufacturers didn't package the products in such concentrated forms.
Earleywine agreed that more information is key.
"I would point out that anyone taking any medication, over-the-counter or underground, should do so only after sufficient education," said Earleywine, a professor of psychology at the State University of New York at Albany. "I'd also emphasize that we still have individual cases of abuse of all kinds of OTC drugs, including aspirin - a drug that's been around since 1899."
He cautioned against overreacting to a single incident with a push for tougher regulations.
The case study was published Sept. 12 in the New England Journal of Medicine