Lipitor is a brand name for atorvastatin, a medication used to lower cholesterol levels in the blood. According to Drug Patent Watch [1], Lipitor belongs to a class of drugs called statins that work by inhibiting an enzyme called HMG-CoA reductase, which is responsible for producing cholesterol in the liver.

A study published in the Circulation journal [2] suggests that atorvastatin can inhibit platelet aggregation, which is the process by which platelets in the blood clump together to form a blood clot. The study found that atorvastatin reduced platelet aggregation by inhibiting the production of a molecule called thromboxane A2, which is involved in the clotting process. However, the study also noted that the effect of atorvastatin on platelet aggregation was relatively weak compared to other antiplatelet drugs.

Another study published in the NCBI [3] suggests that atorvastatin may have a beneficial effect on platelet function in patients with coronary artery disease. The study found that atorvastatin reduced platelet activation and improved platelet responsiveness to antiplatelet drugs in patients with coronary artery disease. However, the study also noted that the effect of atorvastatin on platelet function may vary depending on the patient's individual characteristics and the dose of the medication.

In summary, the available evidence suggests that atorvastatin may have a weak inhibitory effect on platelet aggregation by reducing the production of thromboxane A2. However, the effect of atorvastatin on platelet function may vary depending on the patient's individual characteristics and the dose of the medication. As with any medication, patients should discuss the potential benefits and risks of atorvastatin with their healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ahajournals.org/doi/10.1161/01.cir.0000047060.60595.cc
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3776183/