nephrotoxicity
7 interactions related to nephrotoxicity
tacrolimus + grapefruit
Grapefruit furanocoumarins irreversibly inhibit intestinal CYP3A4, increasing tacrolimus AUC by roughly 28% and Cmax by up to 73%. Case reports describe trough levels tripling after grapefruit ingestion, producing nephrotoxicity and neurotoxicity.
pomelo + tacrolimus
Pomelo contains furanocoumarins that inhibit intestinal CYP3A4 and P-glycoprotein, the two systems that limit tacrolimus absorption. A documented case in a renal transplant patient showed pomelo consumption nearly doubled tacrolimus blood levels, risking nephrotoxicity and neurotoxicity given tacrolimus's narrow therapeutic window.
star fruit + phenytoin
Star fruit (Averrhoa carambola) contains caramboxin, a neurotoxin that activates excitatory neuroreceptors and inhibits GABA, and high oxalate content that causes acute kidney injury. In patients with renal impairment, star fruit ingestion has triggered refractory status epilepticus, directly antagonizing phenytoin's seizure-prevention purpose.
cranberry + tacrolimus
Cranberry juice has been shown to inhibit intestinal CYP3A enzymes, and tacrolimus is heavily metabolized by intestinal CYP3A4 and CYP3A5. The expected direction is an increase in tacrolimus trough levels, raising the risk of nephrotoxicity and tremor, although published cases are scarce and one case unexpectedly reported a decrease.
cbd + tacrolimus
CBD inhibits CYP3A4, CYP3A5, and P-glycoprotein, the main pathways that clear tacrolimus. A published case report documented an approximately 3-fold rise in dose-normalized tacrolimus levels after adding CBD, posing serious nephrotoxicity, neurotoxicity, and over-immunosuppression risk in transplant patients.
cyclosporine + grapefruit
Grapefruit juice contains furanocoumarins that irreversibly inhibit intestinal CYP3A4, raising cyclosporine bioavailability by 35-60% and increasing the risk of nephrotoxicity, hypertension, and neurotoxicity. The effect can persist for 24 hours or longer after a single glass.
tacrolimus + st. john's wort
St. John's wort induces CYP3A4 and P-glycoprotein, slashing tacrolimus blood concentrations and risking acute graft rejection. Conversely, abrupt discontinuation of the herb can unmask tacrolimus nephrotoxicity as levels rebound.