Grapefruit juice can affect Lipitor, a popular statin drug used to lower cholesterol levels. Lipitor's active ingredient is atorvastatin, which is metabolized in the liver by an enzyme called CYP3A4. Grapefruit juice contains compounds that inhibit this enzyme, which can lead to higher levels of atorvastatin in the bloodstream. This can increase the risk of side effects, such as muscle pain, liver damage, and kidney failure [2].

It is recommended that patients taking Lipitor avoid consuming grapefruit juice or eating grapefruit. The effects of grapefruit juice can last for up to 24 hours, so patients should avoid consuming it even if they have taken Lipitor earlier in the day [3]. Patients should also talk to their doctor or pharmacist about any other medications or supplements they are taking, as some of these can also interact with Lipitor [1].

In conclusion, grapefruit juice can affect the metabolism of Lipitor, leading to higher levels of the drug in the bloodstream and an increased risk of side effects. Patients taking Lipitor should avoid consuming grapefruit juice or eating grapefruit and should talk to their doctor or pharmacist about any other medications or supplements they are taking that may interact with Lipitor [2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.goodrx.com/classes/statins/why-cant-i-have-grapefruit-with-my-statin
[3] https://www.health.harvard.edu/heart-health/grapefruit-juice-and-statins