Based on the provided sources, there is no direct evidence to suggest that avocados can decrease the effectiveness of Lipitor, a medication used to lower cholesterol levels.

The first source, Drug Patent Watch, provides information about Lipitor but does not mention any potential interactions between Lipitor and avocados [1].

The second source, Avocado Tea, discusses the potential health benefits of avocado leaves in reducing cholesterol levels. However, it is important to note that this study focuses on avocado leaves, not the fruit itself. Furthermore, the study does not mention Lipitor or any specific cholesterol-lowering medications [2].

The third source, a study published in the National Center for Biotechnology Information (NCBI), discusses the potential benefits of avocados in managing cholesterol levels. The study suggests that avocados may have a positive impact on lipid profiles, including lowering LDL cholesterol levels. However, this study does not specifically address the interaction between avocados and Lipitor [3].

It is always recommended to consult with a healthcare professional or pharmacist regarding any potential interactions between medications and specific foods or supplements. They will be able to provide personalized advice based on your specific health condition and medication regimen.

In conclusion, based on the provided sources, there is no direct evidence to suggest that avocados can decrease the effectiveness of Lipitor. However, it is always best to consult with a healthcare professional for personalized advice.

Sources:
[1] Drug Patent Watch. Lipitor. Retrieved from: https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] Avocado Tea. Avocado Leaf Reduces Cholesterol. Retrieved from: https://avocadotea.com/blogs/health-studies/avocado-leaf-reduces-cholesterol
[3] National Center for Biotechnology Information (NCBI). Avocado consumption and lipid profiles: A systematic review and meta-analysis. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213277/