Lipitor is a medication used to lower cholesterol levels in the blood. According to the Drug Patent Watch [1], Lipitor's active ingredient is atorvastatin calcium, which works by blocking an enzyme that produces cholesterol in the liver. While vitamin D is important for bone health, there is no evidence that it is necessary to supplement vitamin D while taking Lipitor. A study published in PubMed [2] found that atorvastatin did not have any significant effect on vitamin D levels in patients with high cholesterol. However, it is important to maintain adequate vitamin D levels for overall health. According to the Mayo Clinic [3], vitamin D helps the body absorb calcium and is essential for bone health. Vitamin D can be obtained through diet or supplements, and it is recommended that adults get at least 600-800 IU of vitamin D per day. It is always best to consult with a healthcare provider to determine the appropriate vitamin D supplementation while taking Lipitor.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://pubmed.ncbi.nlm.nih.gov/18754003/
[3] https://www.mayoclinic.org/drugs-supplements-vitamin-d/art-20363792