Mechanism
Grapefruit contains furanocoumarins that irreversibly inhibit CYP3A4 enzyme in the gut → drug cannot be metabolized → blood levels increase 3-15x → risk of rhabdomyolysis and liver damage.
Recommendation
Alternatives
Other citrus (orange, lemon, lime) are safe. Grapefruit effect lasts 24h+ after consumption. Pomelo and Seville oranges have the same effect. Some statins (rosuvastatin, pravastatin) are less affected — switch with doctor approval.
⏱️ Duration of Effect
Furanocoumarins inactivate intestinal CYP3A4 for 24-72 hours after a single glass of grapefruit juice.