Based on the provided sources, there is no direct evidence suggesting that Lipitor (atorvastatin) affects REM sleep. Lipitor is a medication primarily used to lower cholesterol levels in the body [1]. It belongs to a class of drugs called statins, which work by inhibiting an enzyme involved in cholesterol production [1].

The first source, DrugPatentWatch, provides information about Lipitor but does not specifically mention any effects on REM sleep [1]. It mainly focuses on the patent status and expiration date of the drug.

The second source, an article from AARP, lists medications that can potentially cause insomnia, but Lipitor is not mentioned [2]. Insomnia is a condition characterized by difficulty falling asleep or staying asleep, and it can affect the different stages of sleep, including REM sleep. However, Lipitor is not included in the list of medications known to cause insomnia in the article.

The third source, a study published in the National Center for Biotechnology Information (NCBI) database, discusses the potential effects of statins on sleep quality [3]. The study suggests that statins, including Lipitor, may have a positive impact on sleep quality by reducing sleep disturbances and improving sleep efficiency [3]. However, the study does not specifically mention REM sleep or provide detailed information on the effects of Lipitor on REM sleep.

In conclusion, based on the provided sources, there is no clear evidence to suggest that Lipitor directly affects REM sleep. However, it is important to note that individual responses to medications can vary, and if you have concerns about your sleep while taking Lipitor, it is recommended to consult with a healthcare professional.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.aarp.org/health/drugs-supplements/info-04-2013/medications-that-can-cause-insomnia.html
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4624738/