Lipitor is a medication used to lower cholesterol levels in the body. It is a brand-name drug that was first approved by the FDA in 1996 [1]. The drug's patent expired in 2011, and since then, several generic versions of Lipitor have become available on the market. According to Drug Patent Watch, there are currently 19 generic versions of Lipitor available in the United States [1].

The availability of generic versions of Lipitor has led to a decrease in the cost of the drug. According to a report by Stat News, patients who use Lipitor and switch to a generic version of the drug can save a significant amount of money on their copays [2]. The report states that in 2017, the average copay for a 30-day supply of Lipitor was $42, while the average copay for a 30-day supply of a generic version of the drug was $10 [2].

The cost savings associated with generic versions of Lipitor are due to a variety of factors. Generic drug manufacturers do not have to spend money on research and development, which allows them to sell their products at a lower cost than brand-name drugs [3]. Additionally, generic drugs are subject to competition, which further drives down their cost [3].

In conclusion, the availability of generic versions of Lipitor has led to a significant decrease in the cost of the drug. Patients who use Lipitor can save a substantial amount of money on their copays by switching to a generic version of the drug. The cost savings associated with generic drugs are due to factors such as lower research and development costs and competition in the market.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.statnews.com/2018/03/12/pbm-copays-brand-name-drugs-generics/
[3] https://www.medicalnewstoday.com/articles/lipitor