Grapefruit juice and statins – Harvard Health
Certain classes of drugs — most notably statins — are metabolized (broken down) in your intestines by an enzyme called CYP3A, which normally reduces the amount of drug that enters your bloodstream. Grapefruit juice contains compounds called furanocoumarins that stop CYP3A from doing its job. As a result, more of the drug is absorbed, making it more powerful than it's meant to be — even toxic in some cases.