Lipitor is a brand name for atorvastatin, a medication used to lower cholesterol levels in the blood. Grapefruit and grapefruit juice can interact with some medications, including Lipitor, which can lead to potentially harmful side effects. According to the Harvard Health Publishing, grapefruit juice can increase the concentration of Lipitor in the blood, which can increase the risk of side effects such as muscle pain, liver damage, and kidney failure. The recommended guidelines for Lipitor and grapefruit is to avoid consuming grapefruit or grapefruit juice while taking Lipitor. Patients should also consult their healthcare provider before consuming any grapefruit products, especially if they are taking Lipitor or other medications. The American Journal of Medicine also recommends that patients taking Lipitor should avoid consuming grapefruit or grapefruit juice to prevent any adverse effects. It is important to follow these guidelines to ensure the safe and effective use of Lipitor.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.health.harvard.edu/heart-health/grapefruit-juice-and-statins
[3] https://www.amjmed.com/article/S0002-9343(15)00774-3/abstract