Acetaminophen and Lipitor are two commonly used drugs that serve different purposes. Acetaminophen is a pain reliever and fever reducer, while Lipitor is a medication used to lower cholesterol levels.

After analyzing the provided sources, it seems that there is no direct interaction between acetaminophen and Lipitor. According to DrugPatentWatch [1], acetaminophen is not known to have any significant interactions with Lipitor.

Furthermore, the National Center for Biotechnology Information [2] explains that acetaminophen is metabolized in the liver, while Lipitor is metabolized in the gut. Therefore, there is no direct interaction between the two drugs.

Additionally, a study published in the Journal of Clinical Pharmacology [3] found that there was no significant interaction between acetaminophen and atorvastatin, the active ingredient in Lipitor. The study concluded that there was no need to adjust the dose of Lipitor when taken with acetaminophen.

In conclusion, based on the provided sources, there is no evidence to suggest that acetaminophen affects the effectiveness of Lipitor. However, it is always important to consult with a healthcare professional before taking any medications, especially if you are taking multiple drugs at the same time.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ACETAMINOPHEN
[2] https://www.ncbi.nlm.nih.gov/books/NBK548162/
[3] https://pubmed.ncbi.nlm.nih.gov/18847329/