There is no direct information available in the provided sources that specifically discuss the impact of dairy on Lipitor's effectiveness. However, based on the general knowledge of how Lipitor works and the role of dairy in the human body, it is possible to make some educated assumptions.

Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. It works by blocking a substance your body needs to make cholesterol [1]. Dairy products, on the other hand, contain various nutrients like calcium, vitamin D, and protein. They do not have a direct impact on the mechanism of action of Lipitor [2][3].

However, it is important to note that some dairy products, particularly those that are full-fat, can contribute to increased cholesterol levels in the body. This could potentially counteract the effects of Lipitor. Therefore, it is generally recommended to consume low-fat or fat-free dairy products as part of a heart-healthy diet when taking Lipitor [3].

In conclusion, while there is no direct evidence that dairy impacts Lipitor's effectiveness, it is advisable to consume low-fat or fat-free dairy products as part of a heart-healthy diet when taking this medication to manage cholesterol levels.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.webmd.com/vitamins/ai/ingredientmono-138/milk-thistle
[3] https://www.medicalnewstoday.com/articles/248136