Lipitor is a medication used to treat high cholesterol levels in the blood. Aspirin is a medication used to relieve pain and inflammation and to prevent blood clots.

According to the Drug Patent Watch [1], there is no known interaction between Lipitor and aspirin that would reduce the effectiveness of aspirin. However, it is important to note that individuals taking both medications should consult with their healthcare provider to ensure that there are no contraindications or interactions.

A study published in the Journal of Experimental & Clinical Cancer Research [2] investigated the effect of Lipitor on the efficacy of aspirin in preventing cancer. The study found that Lipitor did not reduce the effectiveness of aspirin in preventing cancer. In fact, the study suggested that Lipitor may enhance the anti-cancer effects of aspirin.

Another study published in the Journal of Cardiovascular Pharmacology [3] investigated the interaction between Lipitor and aspirin in patients with coronary artery disease. The study found that there was no significant interaction between the two medications and that the combination of Lipitor and aspirin was safe and effective in reducing the risk of cardiovascular events.

In conclusion, there is no evidence to suggest that Lipitor reduces the effectiveness of aspirin. However, it is important for individuals taking both medications to consult with their healthcare provider to ensure that there are no contraindications or interactions.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://jeccr.biomedcentral.com/articles/10.1186/s13046-016-0304-4
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738023/