Intravenous administration of cannabis and lethal anaphylaxis

Cannabis allergy appears to be increasing. A 33-year-old woman is reported who collapsed and died shortly after injecting herself with a cannabis solution prepared by pouring boiling water onto plant material. There were no significant findings at autopsy, except for a single recent venepuncture wound in the left cubital fossa. Toxicological examination of the blood revealed low levels of methylamphetamine and amphetamine with tetrahydrocannabinol (Δ⁹-THC) and 11-nor-9-carboxy-Δ⁹-THC, and no opiates. The syringe used by the decedent contained Δ⁹-THC. Serum tryptase levels were markedly elevated (>200 µg/L; N < 12 µg/L). This finding coupled with the sudden collapse after injecting an aqueous extract of cannabis indicated a likely anaphylactic or anaphylactoid reaction to the extract. Cannabis allergy may occur following handling, inhalation, swallowing or injecting Cannabis sativa plants or their products. The possibility of an allergic reaction should therefore be considered at autopsy in deaths where there has been recent contact with cannabis.