Lipitor (atorvastatin) is a medication used to lower cholesterol levels in the blood. It is important to take Lipitor as prescribed by a healthcare provider. According to the National Health Service (NHS) [2], Lipitor should be taken once a day, preferably in the evening, with or without food. However, the website Drugs.com [3] suggests that it is better to take Lipitor with food to increase its absorption and effectiveness. The absorption of Lipitor can be affected by food, so it is recommended to take it with a meal or a snack. Patients should avoid grapefruit and grapefruit juice while taking Lipitor, as it can increase the risk of side effects. It is important to follow the healthcare provider's instructions and to read the medication label carefully before taking Lipitor. Patients should not change the dosage or stop taking Lipitor without consulting their healthcare provider. [2][3]

Sources:
[2] https://www.nhs.uk/medicines/atorvastatin/how-and-when-to-take-atorvastatin/
[3] https://www.drugs.com/medical-answers/eat-food-taking-atorvastatin-3565628/