Introduction: Calcineurin inhibitor (CNI) based regimens afford the greatest protection against acute rejection and are used in > 90% of kidney transplant recipients. Cannabidiol (CBD) has been advertised as a natural remedy to treat several disorders. Information on the concurrent use of CBD and tacrolimus is limited. Herein we describe four cases of patients reporting CBD use post kidney transplant, and the effects on tacrolimus drug levels.

Results: 

• Case 1: 38-year-old male with chronic kidney disease secondary to polycystic kidney disease (PKD) received a living unrelated kidney transplant from his spouse.His course was uncomplicated until 3 months post-transplant when he started using CBD oil for sleep. . One week after starting CBD oil he presented for follow up and was noted to have a tacrolimus level of 40.1 ng/mL.  His tacrolimus level returned at 20 ng/mL after stopping CBD oil.
• Case2: A 55-year-old male with chronic kidney disease secondary to lithium toxicity received a living unrelated kidney transplant. He self-started CBD oil three weeks post-transplant and was noted to have an increase in tacrolimus level to 16.1 ng/mLHe elected to stop his CBD oil because he thought it may be interfering with his medications and four days later his tacrolimus levels decreased to 8.8 ng/mL.
• Case3: 46 year old male with ESRD ascribed to diabetes mellitus received a deceased donor kidney transplant.One year later he presented for a routine follow up with a serum creatinine of 3.7 mg/dL with a tacrolimus level of 2.4 ng/mLHe reported taking CBD oil for the past 6 weeks for anxiety.His tacrolimus was increased, and he underwent a kidney transplant biopsy which showed acute cell mediated and vascular rejection with chronic active antibody mediated rejection. HLA testing showed de novo HLA antibodies to DQ7 and DQA1*05.
• Case 4: 64 yr old female received her pancreas transplant in 2005.14 years later patient presented for a routine follow up and was noticed to have a tacrolimus level of 12.1 while on a steady dose of 1 mg BID. She endorsed starting CBD oil a month prior for relief of her neuropathy symptoms.Her tacrolimus was adjusted down to 0.5 mg BID with improvement inher level to 7.

Discussion: Cannabidiol (CBD) is a non-psychogenic cannabinoid found in the Cannibis sativa plant. The Agriculture Improvement Act of 2018 legalized production of industrial hemp plants, so long as it contained no more than 0.3% of delta-9-tetrahydrocannabinol (THC).Interestingly, amongst our cases 3 resulted in an increase in tacrolimus levels and another resulted in a marked decrease in tacrolimus levels which precipitated allograft rejection. all cases of increased levels occurred without a change in tacrolimus dosing and relative stable levels prior to known administration. Tacrolimus levels improved after stopping CBD oil supplements. The solitary case of reduced tacrolimus levels following CBD oil exposure i may have been related to another compound within the CBD oil labelled product.