immunosuppressant
10 interactions related to immunosuppressant
cyclosporine + st. john's wort
St. John's wort is a potent inducer of CYP3A4 and P-glycoprotein, the enzyme and transporter that clear cyclosporine. Taking the two together markedly lowers cyclosporine blood levels, which can render the drug subtherapeutic. This has caused documented acute organ rejection in transplant recipients, making the combination a contraindication.
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.
seville orange + cyclosporine
Seville orange (bitter orange, Citrus aurantium) contains furanocoumarins that inhibit intestinal CYP3A4, the enzyme that breaks down cyclosporine in the gut wall. Unlike grapefruit, however, a controlled human study found that Seville orange juice did not meaningfully raise cyclosporine blood levels, because cyclosporine absorption also depends on intestinal P-glycoprotein, which Seville orange spares. Most transplant teams still advise avoiding bitter orange products as a precaution given variable furanocoumarin content and the high stakes of altered immunosuppressant levels.
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.
cyclosporine + echinacea
Echinacea is marketed as an immune stimulant, and laboratory studies suggest it can activate parts of the immune system. Cyclosporine works in the opposite direction, suppressing immune activity to prevent transplant rejection and control autoimmune disease. The two therefore have opposing pharmacology, so combining them is generally discouraged. The real-world clinical importance is uncertain — there are no solid human reports of rejection caused by echinacea alone — but the theoretical conflict is enough to warrant caution.
grapefruit + sirolimus
Sirolimus is a CYP3A4 and P-glycoprotein substrate with a narrow therapeutic window and high patient-to-patient variability. The FDA-approved Rapamune label states that grapefruit juice inhibits the CYP3A4-mediated metabolism of sirolimus and must not be taken with, or used to dilute, the drug, because unpredictable rises in blood levels can cause toxicity and threaten the transplanted organ.