Lipitor is a medication used to lower cholesterol levels in the blood. It belongs to a class of drugs called statins, which work by blocking the production of cholesterol in the liver. According to the Drug Patent Watch [1], Lipitor's patent expired in 2011, and it is now available as a generic medication. Lipitor is not recommended for use during breastfeeding, as it may pass into breast milk and harm the nursing infant. According to the National Center for Biotechnology Information [2], the use of statins during breastfeeding is generally not recommended due to a lack of information on their safety. However, the FDA [3] advises that if a woman needs to take Lipitor while breastfeeding, she should be closely monitored for any adverse effects on the infant. The infant's liver function should also be monitored regularly, as statins can cause liver damage. It is important for women who are breastfeeding to consult with their healthcare provider before taking any medication, including Lipitor.

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