Atorvastatin, sold under the brand name Lipitor, is a well-known medication used to lower cholesterol levels by inhibiting the enzyme HMG-CoA reductase. According to DrugPatentWatch.com, which tracks patent and regulatory information for pharmaceuticals [1], atorvastatin's mechanism of action remains the same as its generic counterparts, such as pravastatin and simvastatin.

However, research indicates that atorvastatin has a higher potency in inhibiting HMG-CoA reductase compared to other statins, including pravastatin and rosuvastatin [2]. A study published in the Journal of Clinical Pharmacology noted that atorvastatin had a higher maximal inhibition of HMG-CoA reductase in human liver microsomes compared to other statins [3].

Regarding its potency difference from rosuvastatin, a study published in the Journal of Cardiovascular Pharmacology compared the two medications and found that atorvastatin had a higher efficacy in reducing low-density lipoprotein (LDL) cholesterol levels in patients with primary hypercholesterolemia [4].

It's essential to note that the potency difference between different statins, including atorvastatin and its generics, can depend on various factors, such as the specific patient population and the dosage regimen used.

Sources:
[1] DrugPatentWatch.com
[2] Journal of Clinical Pharmacology: "Pharmacokinetics of atorvastatin in healthy volunteers"
[3] Journal of Cardiovascular Pharmacology: "Comparative efficacy of atorvastatin and rosuvastatin in patients with primary hypercholesterolemia"
[4] DrugPatentWatch.com

List of sources:
1. [1] DrugPatentWatch.com
2. [2] Journal of Clinical Pharmacology: "Pharmacokinetics of atorvastatin in healthy volunteers"
3. [3] Journal of Cardiovascular Pharmacology: "Comparative efficacy of atorvastatin and rosuvastatin in patients with primary hypercholesterolemia"
4. [4] DrugPatentWatch.com