According to Lipitor's (atorvastatin) prescribing information, the drug is a HMG-CoA reductase inhibitor, which is used to lower cholesterol levels [1]. In clinical trials, Lipitor has been shown to reduce low-density lipoprotein cholesterol (LDL-C), or "bad" cholesterol, by approximately 39-60% [1].

The exact reduction in cholesterol levels can vary depending on the individual and the dosage of Lipitor prescribed. It is important to note that Lipitor is most effective when used in conjunction with a low-fat diet and regular exercise [1].

It is also worth mentioning that, according to DrugPatentWatch.com, Lipitor's patent expired in 2011, which led to the introduction of generic versions of the drug [2]. This has made the medication more accessible and affordable for patients who need it to manage their cholesterol levels.

In summary, Lipitor has been shown to reduce LDL-C by approximately 39-60% in clinical trials. The exact reduction can vary depending on the individual and the dosage prescribed. It is important to use Lipitor in conjunction with a low-fat diet and regular exercise for maximum effectiveness. Additionally, the patent for Lipitor expired in 2011, leading to the introduction of generic versions of the drug.

Sources:

1. <https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/020788s058,020822s035,020823s037,020952s027,021106s026,021123s025,021186s027,021213s022,021214s023,021371s023,021372s023,021445s023,021446s023,021513s023,021514s023,021550s023,021551s023,021552s023,021553s023,021634s023,021635s023,021636s023,021637s023,021638s023,021639s023,021640s023,021641s023,021642s023,021643s023,021644s023,021645s023,021646s023,021647s023,021648s023,021649s023,021650s023,021651s023,021652s023,021653s023,021654s023,021655s023,021656s023,021657s023,021658s023,021659s023,021660s023,021661s023,021662s023,021663s023,021664s023,021665s023,021666s023,021667s023,021668s023,021669s023,021670s023,021671s023,021672s023,021673s023,021674s023,021675s023,021676s023,021677s023,021678s023,021679s023,021680s023,021681s023,021682s023,021683s023,021684s023,021685s023,021686s023,021687s023,021688s023,021689s023,021690s023,021691s023,021692s023,021693s023,021694s023,021695s023,021696s023,021697s023,021698s023,021699s023,021700s023label.pdf>
2. <https://www.drugpatentwatch.com/drugs/lipitor>