Lipitor is a medication used to lower cholesterol levels in the blood. According to Drug Patent Watch [1], Lipitor's active ingredient is atorvastatin calcium, which is a type of statin drug. Statins are a class of drugs used to lower cholesterol levels in the blood.

Grapefruit and grapefruit juice are known to interact with many medications, including some statins [2]. According to Healthline [2], grapefruit and grapefruit juice can increase the levels of atorvastatin in the blood, which can increase the risk of side effects. Therefore, it is recommended to avoid grapefruit and grapefruit juice while taking Lipitor.

However, there is no evidence to suggest that other citrus fruits, such as oranges or lemons, interact with Lipitor [3]. A study published in the Journal of Clinical Lipidology [3] found that consuming orange juice did not affect the absorption or effectiveness of atorvastatin.

In summary, grapefruit and grapefruit juice are known to interact with Lipitor, but there is no evidence to suggest that other citrus fruits do. Therefore, it is recommended to avoid grapefruit and grapefruit juice while taking Lipitor. As always, it is important to talk to a healthcare provider before making any changes to medication or diet.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.healthline.com/health/high-cholesterol/grapefruit-and-statins
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3589309/