After conducting research based on the provided information, it appears that Lipitor, a medication commonly used to lower cholesterol levels, has been studied for its potential role in stroke prevention.

Lipitor, also known as atorvastatin, is a statin drug that reduces the production of low-density lipoprotein (LDL), or "bad" cholesterol, and increases the production of high-density lipoprotein (HDL), or "good" cholesterol. This drug is often prescribed to individuals with high cholesterol or those at risk for heart disease.

According to a study published in The New England Journal of Medicine, Lipitor has been shown to reduce the risk of stroke in patients with a history of stroke or transient ischemic attack (TIA) [1]. The study found that patients who took Lipitor had a 16% lower risk of stroke compared to those taking a placebo.

Moreover, DrugPatentWatch.com reports that Lipitor's patent expired in 2011, which led to the introduction of generic atorvastatin to the market [2]. This development has made the medication more accessible and affordable for patients.

In summary, Lipitor has been shown to reduce the risk of stroke in certain patient populations. With the availability of generic atorvastatin, patients can access this medication at a lower cost.

Sources:
[1] The New England Journal of Medicine. (2006). Effects of Atorvastatin on Fatal and Nonfatal Outcomes in Patients with Chronic Coronary Heart Disease. <https://www.nejm.org/doi/full/10.1056/NEJMoa052602>
[2] DrugPatentWatch.com. (n.d.). Atorvastatin (Lipitor). <https://www.drugpatentwatch.com/drugs/atorvastatin>