Lipitor is a brand name for the drug atorvastatin, which is a type of medication known as a statin. Statins are used to lower cholesterol levels and reduce the risk of heart disease. Grapefruit juice can interact with certain medications, including some statins, and affect their effectiveness. According to a Harvard Health Publishing article [2], grapefruit juice can interfere with the enzymes in the liver that metabolize statins, leading to an increase in the level of the drug in the bloodstream. This can increase the risk of side effects, such as muscle pain and liver damage. GoodRx [3] also warns that grapefruit juice can increase the risk of side effects and advises patients to avoid consuming grapefruit or grapefruit juice while taking statins, including Lipitor. However, Drug Patent Watch [1] does not mention grapefruit as an interaction for Lipitor. It is always important to consult with a healthcare provider before consuming grapefruit or grapefruit juice while taking Lipitor or any other medication.

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