Unexplained Bleeding Linked to Rat Poison in Synthetic Cannabinoids

Unexplained bleeding in dozens of patients with a history of synthetic cannabinoid (SCB) use was linked to poisoning with brodifacoum, an anticoagulant often used in rat poison, Florida health officials reported.

In early December 2021, the Florida Poison Information Center Tampa notified the Florida Department of Health about three patients experiencing bleeding with an unclear cause, reported Nikki Coble, MPH, of the Florida Department of Health in Hillsborough County in Tampa, and colleagues.

“These patients resembled those from the nationwide incident of coagulopathy associated with SCB use that occurred in 2018, which included five patients from Florida who displayed similar signs, symptoms, and high-risk behaviors,” Coble’s group wrote in the Morbidity and Mortality Weekly Report (MMWR).

On December 7, epidemiology program managers at county health departments, including those in Pasco, Pinellas, and Polk counties, as well as emergency department physicians and medical examiners at Advent Health, St. Joseph Hospital, and Tampa General Hospital were informed about the three patients and asked to report any suspected cases. Additional notification and identification efforts included the issuance of a press release to help public awareness and the use of Florida’s syndromic surveillance database.

Patients were interviewed and medical records were reviewed to collect information on signs and symptoms, marijuana or other drug use, product purchase locations, and potential exposure to prescription vitamin K oxidoreductase antagonists.

A total of 52 cases were ultimately identified (mean age 36, 76.9% men), 83% of which were confirmed, including four patients, with a mean age of 34, who died. Forty-seven of these patients reported using SCBs with similar purchase locations before symptom onset, Coble and team noted.

The most common symptoms were hematuria, abdominal pain, and hematemesis. International normalized ratio (INR) measurements — which are used to determine how long blood takes to form a clot — were elevated in all patients.

Five patients provided the SCB products they had smoked, four of which tested positive for brodifacoum, a long-acting vitamin K oxidoreductase antagonist.

All patients were treated with vitamin K1, administered by both oral and intravenous routes, which is used to treat vitamin K oxidoreductase antagonist coagulopathy.

“Communicating timely information to healthcare providers and the general public allowed for additional patient identification and was crucial to connecting with patients who needed medical care,” Coble’s group wrote.

However, they noted the potential issue of treatment expense with oral vitamin K1, which can top $65,000 a month. Two-thirds of the patients were uninsured, but 12 were ultimately enrolled in a local managed healthcare program, and a pharmaceutical company donated enough K1 tablets to treat all of the 52 patients.

Furthermore, diagnosis of brodifacoum poisoning was difficult, since required testing costs more than $750 per specimen and has a long turnaround time, given that it is only offered by a single private laboratory. Coble and team also said that there was a limited supply of the high doses of vitamin K1 during the extended period of time required for treatment, and that patient compliance can pose problems because of the high cost and cumbersome nature of the treatment.

“To help avert future distribution of brodifacoum-laced SCB products, local county law enforcement was informed of this incident and provided information regarding the locations where patients reported they had purchased SCB products,” Coble and team noted.