Medical Marijuana Induced Tacrolimus Toxicity

Abstract As both recreational and therapeutic marijuana use increases in the US, more attention is being paid to its direct medical and psychoactive effects. One crucial dimension is the potential for marijuana or marijuana-derived therapies to interact with other prescribed medications. Tacrolimus is an immunosuppressant medication prescribed to prevent rejection in patients receiving solid organ and bone marrow transplants. Clinically, it is characterized by a narrow therapeutic index and multiple drug-drug interactions. Constituents in marijuana are known to inhibit cytochrome P-450 3A, which is normally responsible for metabolizing tacrolimus, leading to the potential for a dangerous interaction. Though this phenomenon has been described previously in a stem cell transplant patient 1 , we present the case of medical marijuana induced tacrolimus toxicity in a patient who recently received an orthotopic liver transplant.