An outbreak of severe coagulopathy in northern Israel among users of illicit synthetic cannabinoids adulterated with brodifacoum

Introduction Adulteration of illicit drugs is a well-known phenomenon that may expose consumers to unexpected adverse effects. We report a large outbreak of severe coagulopathy in northern Israel during nine months in 2021–2022 among users of synthetic cannabinoids adulterated with a long-acting anticoagulant, brodifacoum.Methods We performed a retrospective cohort study based on data extracted from the Israeli National Poison Information Center database and from electronic medical patient records at three participating hospitals. Confiscated drug samples and blood samples obtained at admission in a subgroup of patients were tested for the presence of long-acting anticoagulants.Results We identified 98 patients affected by the outbreak. All patients had a prolonged international normalized ratio on admission, and in 69%, the blood was non-coagulating. For patients treated in the three participating centers (n = 72), the presenting complaint was overt bleeding in 79% of patients, most commonly in the urinary (53%) and gastrointestinal tracts (50%). The most severe complications were intracranial bleeding (4%), hemothorax (3%), pericardial bleeding (1%), and four patients died. Brodifacoum was detected in all available blood samples (median concentration 207 µg/L, interquartile range 112–349 μg/L, range 45–1,118 µg/L), and the drug samples contained both brodifacoum and the synthetic cannabinoid ADB-BUTINACA. All patients were treated with high-dose phytomenadione (vitamin K1) and additionally by packed red blood cell transfusions, fresh frozen plasma, and/or 4-factor prothrombin complex concentrate when indicated. The most frequent phytomenadione (vitamin K1) dose regimen was initially 20 mg intravenously every eight hours, and at discharge, 20 mg orally three times daily.Conclusions Outbreaks of severe coagulopathies in users of synthetic cannabinoids adulterated with a long-acting anticoagulant continue to erupt in different regions of the world. Rapid recognition of an outbreak requires a high index of suspicion when confronting young, otherwise healthy subjects with otherwise unexplained severe coagulopathy.