Lipitor is a brand name for atorvastatin, a medication used to lower cholesterol levels in the blood. According to DrugPatentWatch [1], Lipitor works by blocking an enzyme in the liver that produces cholesterol, which results in a decrease in cholesterol levels in the blood.

The Mayo Clinic [2] explains that vitamin D is a fat-soluble vitamin that is important for the absorption of calcium and bone health. However, it is not clear how Lipitor affects the absorption of vitamin D. It is recommended that people taking Lipitor should have their vitamin D levels checked regularly and consider taking a vitamin D supplement if necessary.

ConsumerLab [3] states that some supplements, such as red yeast rice, may interact with statins, including Lipitor, and increase the risk of side effects such as muscle pain and liver damage. It is important to talk to a healthcare provider before taking any supplements while on Lipitor.

In summary, Lipitor works by blocking an enzyme in the liver that produces cholesterol, but it is not clear how it affects the absorption of vitamin D. People taking Lipitor should have their vitamin D levels checked regularly and talk to their healthcare provider before taking any supplements, including red yeast rice.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.mayoclinic.org/drugs-supplements-vitamin-d/art-20363792
[3] https://www.consumerlab.com/answers/which-drugs-should-be-avoided-when-taking-statins/statin-supplement-interactions/