Lipitor (atorvastatin) is a medication used to lower cholesterol levels in the blood. According to the sources provided, there are no specific absorption requirements for Lipitor. However, there are some general guidelines that should be followed to ensure optimal absorption.

According to the drug label provided by the FDA [3], Lipitor should be taken orally once a day, with or without food. It is recommended to take Lipitor at the same time every day. The label also advises that the dosage of Lipitor should be individualized based on the patient's cholesterol levels and response to treatment.

The absorption of Lipitor is not affected by food, but it is recommended to avoid consuming grapefruit or grapefruit juice while taking Lipitor [3]. Grapefruit can increase the levels of Lipitor in the blood, which can lead to side effects.

According to a study published in the National Library of Medicine [2], the absorption of Lipitor is not affected by age, gender, or race. However, the study did find that the absorption of Lipitor was slightly reduced in patients with liver disease.

In conclusion, there are no specific absorption requirements for Lipitor. It should be taken orally once a day, with or without food, and at the same time every day. Patients should avoid consuming grapefruit or grapefruit juice while taking Lipitor. The dosage of Lipitor should be individualized based on the patient's cholesterol levels and response to treatment.

Sources:
[2] https://www.ncbi.nlm.nih.gov/books/NBK430779/
[3] https://www.accessdata.fda.gov/drugsatfda_docs/label/2009/020702s057lbl.pdf