Medical Marijuana Overdose Sends Man to ER

— Case report highlights risks of high-strength THC products in patients' hands


A man's overdose of tetrahydrocannabinol (THC) may serve as a warning about risks associated with highly concentrated cannabis products available as "medical marijuana."

As reported in the New England Journal of Medicine, the 52-year-old man with a brain tumor arrived at the emergency department with acute delirium. His wife told staff that he had been experiencing increasing restlessness and garbled speech during the previous 2 days.

Jeanmarie Perrone, MD, and colleagues at the Hospital of the University of Pennsylvania in Philadelphia, noted that at presentation the patient "was awake, but unable to answer questions, intermittently redirectable, and in a state of hyperactive delirium."

Perrone told MedPage Today that testing to determine if the delirium was caused by the patient's brain tumor turned up nothing. When the ER docs examined the patient's medications, they found a syringe, which his wife said was used to administer a liquid marijuana formulation.

"They were using it to try to stimulate his appetite, but I'm not sure if any of his doctors knew about it. I don't think they did," Perrone said.

The product's packaging revealed that the 1-mL syringe held approximately 500 mg of 65.9% THC. About two-thirds had been used -- a total of 330 mg THC, apparently consumed orally over several days.

"A typical recreational dose is around 10 mg, so this was a highly concentrated product," Perrone said, adding that the patient was taking it a drop or two at a time. "That doesn't sound like a lot, but in this case it was enough to cause the disorientation."

Once in the hospital, the man's mental symptoms receded.

Standardized dosing instructions do not exist for highly concentrated THC products used for medical reasons and the burden is on the patient to understand dosing, Perrone pointed out.

A total of 33 states and the District of Columbia now allow the use of marijuana to treat various medical conditions, although medical marijuana laws vary widely from state to state.

Perrone said with the increased use of medical THC and cannabidiol (CBD) products by patients with serious medical issues, "there is a whole new field of regulatory issues that need to be addressed."

In their correspondence to NEJM, Perrone and colleagues called for regulation and monitoring of THC and CBD products used for medical purposes.

"With the increasing use of medical marijuana, it is time for regulations to standardize and monitor these substances," the authors wrote.

Moreover, there are currently no state or national databases to report adverse effects related to medical marijuana use, Perrone noted.

The federal government's drug adverse event monitoring program, MedWatch, which is administered by the FDA, does not accept reports on CBD products that are not federally approved.

"Packaging changes to prevent such extremely concentrated [THC] formulations and a central agency for reporting, research, and regulation are overdue," Perrone and colleagues concluded.

Last Updated September 13, 2019


Perrone and co-authors reported having no relevant conflicts of interest.

Primary Source

New England Journal of Medicine

Source Reference: Mudan AA, et al "Medical marijuana miscalculation" N Engl J Med 2019; DOI: 10.1056/NEJMc1907013.