nephrotoxicity
7 interactions related to nephrotoxicity
tacrolimus + grapefruit
Grapefruit furanocoumarins irreversibly inhibit intestinal CYP3A4, the enzyme that limits how much tacrolimus reaches the bloodstream. This can raise tacrolimus blood levels enough to cause kidney and nervous-system toxicity. Because the enzyme inhibition lasts for days, separating dose timing does not prevent it.
pomelo + tacrolimus
Pomelo contains furanocoumarins that inhibit intestinal CYP3A4 and P-glycoprotein, the systems that limit how much tacrolimus is absorbed. A documented case in a renal transplant patient showed pomelo consumption raised tacrolimus blood levels, and tacrolimus has a narrow therapeutic window where small swings can cause kidney or nervous-system toxicity, or under-immunosuppression and rejection.
star fruit + phenytoin
Star fruit (Averrhoa carambola) contains caramboxin, a neurotoxin that excites neurons, plus soluble oxalates that can injure the kidneys. In people with reduced kidney function, who cannot clear caramboxin, eating star fruit has triggered intractable seizures and status epilepticus. This is the fruit's own toxicity rather than a chemical reaction with phenytoin, but for someone taking phenytoin to prevent seizures it adds a serious, avoidable risk.
cranberry + tacrolimus
The only human report on cranberry and tacrolimus showed tacrolimus levels falling sharply, not rising; lab studies predict the opposite, so the true direction is genuinely unpredictable. Because tacrolimus has a very narrow therapeutic window, any change in cranberry intake deserves a trough check.
cbd + tacrolimus
CBD inhibits CYP3A4, CYP3A5, and P-glycoprotein, the main pathways that clear tacrolimus. Case reports and a controlled pharmacokinetic trial show that adding CBD raises tacrolimus blood levels substantially, risking nephrotoxicity, neurotoxicity, and over-immunosuppression in transplant recipients, while stopping CBD abruptly can let levels crash and risk rejection.
cyclosporine + grapefruit
Grapefruit contains furanocoumarins that irreversibly inhibit intestinal CYP3A4, the enzyme that normally breaks down cyclosporine before it is absorbed. This meaningfully raises cyclosporine blood levels and, because cyclosporine has a narrow safety margin, increases the risk of kidney injury, high blood pressure, and neurological side effects. The effect persists for about a day or longer after a single serving.
tacrolimus + st. john's wort
St. John's wort induces the CYP3A4 enzyme and the P-glycoprotein transporter, which speeds up clearance of tacrolimus and lowers its blood levels, raising the risk of transplant rejection. Stopping the herb after the body has adjusted can let tacrolimus levels rebound, which has been linked to kidney toxicity.