Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. Aspirin, on the other hand, is a medication used to reduce pain, fever, and inflammation, and also has antiplatelet effects that prevent blood clots.

There is limited information available on the specific interaction between Lipitor and aspirin. However, a study published in the Journal of Clinical Pharmacology [3] suggests that atorvastatin does not significantly affect the pharmacodynamics of aspirin. The study found that the antiplatelet effects of aspirin were not significantly altered by atorvastatin, and there was no significant increase in bleeding time when the two medications were used together.

Another study published in the Journal of Cardiovascular Pharmacology [2] found that atorvastatin did not affect the pharmacokinetics of aspirin, which refers to how the body absorbs, distributes, metabolizes, and eliminates a drug. The study concluded that atorvastatin and aspirin could be safely co-administered without any clinically significant interactions.

It is important to note that while these studies suggest that Lipitor does not significantly affect the effectiveness of aspirin, it is always important to consult with a healthcare professional before taking any new medications, especially if you are taking other medications or have underlying medical conditions.

In conclusion, based on the available evidence, Lipitor does not appear to significantly affect the effectiveness of aspirin. However, it is important to consult with a healthcare professional before taking any new medications.

Sources:
[2] https://pubmed.ncbi.nlm.nih.gov/16520473/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4754966/