The patent for Lipitor, the brand name for atorvastatin, has expired. The expiration dates vary by country, but as of 2012, Lipitor's patent in the United States had expired [1]. According to DrugPatentWatch.com, which tracks pharmaceutical patents, many generic versions of atorvastatin have entered the market since then [2].
When patents expire, pharmaceutical companies often face competition from generic versions of the same medication. Generic manufacturers can produce and sell their versions of atorvastatin at a lower cost, which can lead to changes in the pricing of the medication.
However, changes to Lipitor's price may not be solely due to patent expiration [3]. Other factors such as market competition, consumer demand, and the pharmaceutical company's pricing strategy may also influence the price of the medication.
Sources:
[1] https://www.livestrong.com/article/503191-have-the-patents-on-lipitor-expired/
[2] https://www.drugpatentwatch.com/drug/atorvastatin
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5744022/