Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. It is a member of the statin drug class and is widely prescribed for the treatment of hypercholesterolemia [1].

According to a study published in the Journal of Clinical Lipidology, atorvastatin is an effective medication for reducing low-density lipoprotein (LDL) cholesterol levels. The study found that atorvastatin reduced LDL cholesterol levels by an average of 37% after 12 weeks of treatment [2].

Another study published in the Journal of the American College of Cardiology compared the effectiveness of atorvastatin to other statins. The study found that atorvastatin was more effective than simvastatin and pravastatin in reducing LDL cholesterol levels [3].

In terms of patent protection, Lipitor's patent expired in 2011, which led to the introduction of generic versions of the drug. However, the effectiveness of the generic versions may vary depending on the manufacturer [1].

In conclusion, Lipitor (atorvastatin) is an effective medication for reducing LDL cholesterol levels. Studies have shown that it is more effective than other statins in reducing LDL cholesterol levels. However, the effectiveness of generic versions of the drug may vary depending on the manufacturer.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859299/
[3] https://pubmed.ncbi.nlm.nih.gov/12860216/