Lipitor is a prescription medication that is used to lower cholesterol levels in the blood. It contains the active ingredient atorvastatin calcium, which belongs to a class of drugs known as HMG-CoA reductase inhibitors or statins. According to the Drug Patent Watch [1], Lipitor was first approved by the FDA in 1996 and has been a widely used medication since then.

Atorvastatin works by blocking an enzyme in the liver that is responsible for producing cholesterol. By reducing the amount of cholesterol produced by the liver, Lipitor can help to lower the levels of LDL or "bad" cholesterol in the blood. According to the National Center for Biotechnology Information [2], atorvastatin has been shown to be effective in reducing LDL cholesterol levels by up to 60%.

The FDA-approved label for Lipitor [3] indicates that the medication has been shown to reduce the risk of heart attack, stroke, and certain types of heart surgery in patients with multiple risk factors for heart disease. Lipitor has also been shown to reduce the risk of heart attack and stroke in patients with type 2 diabetes who have other risk factors for heart disease.

In conclusion, Lipitor (atorvastatin calcium) is a medication that is used to lower cholesterol levels in the blood. It has been shown to be effective in reducing LDL cholesterol levels and reducing the risk of heart attack, stroke, and certain types of heart surgery in patients with multiple risk factors for heart disease.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/books/NBK548236/
[3] https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/020702s073lbl.pdf