Lipitor, also known as atorvastatin, is a prescription medication used to lower cholesterol levels in the blood. Grapefruit juice can interact with some medications, including statins like Lipitor, by inhibiting the enzyme responsible for breaking down the drug in the body. This can lead to higher levels of the medication in the bloodstream, increasing the risk of side effects [2]. Therefore, grapefruit juice is not recommended for people taking Lipitor [2][3]. Lowering the dosage of Lipitor should only be done under the guidance of a healthcare professional and should not be done in combination with grapefruit juice [3]. It is important to follow the dosage instructions provided by the healthcare provider and to inform them of any potential interactions or side effects experienced while taking Lipitor [1][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.health.harvard.edu/heart-health/grapefruit-juice-and-statins
[3] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013