Lipitor is a statin drug that is used to lower cholesterol levels in the blood. Grapefruit is known to interact with certain medications, including some statins, by increasing their potency and causing side effects. According to the sources provided, grapefruit can increase the side effects of Lipitor, such as muscle pain, weakness, and liver damage [2][3]. This is because grapefruit contains compounds that inhibit the enzymes responsible for breaking down Lipitor in the body, leading to higher levels of the drug in the bloodstream [3]. Therefore, it is recommended that patients taking Lipitor should avoid consuming grapefruit or grapefruit juice [2][3]. Patients should also consult their doctor or pharmacist for more information on how to safely take Lipitor and avoid any potential drug interactions [3].

Sources:
[2] https://www.goodrx.com/classes/statins/why-cant-i-have-grapefruit-with-my-statin
[3] https://www.nhs.uk/common-health-questions/medicines/does-grapefruit-affect-my-medicine/