furanocoumarins
2 interactions related to furanocoumarins
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.
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.