Lipitor is a prescription medication used to lower cholesterol levels in the blood. The active ingredient in Lipitor is atorvastatin calcium [1]. According to the FDA, Lipitor is excreted into human milk, and nursing should be discontinued while taking Lipitor [3]. The National Center for Biotechnology Information also confirms that atorvastatin is excreted into human milk and advises against its use during breastfeeding [2]. Therefore, it is not recommended to take Lipitor while breastfeeding.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/books/NBK501361/
[3] https://www.fda.gov/media/150774/download