Lipitor (atorvastatin) lowers cholesterol levels by inhibiting HMG-CoA reductase, an enzyme the liver uses to produce cholesterol. This reduces low-density lipoprotein (LDL) cholesterol, or "bad" cholesterol, by 35-60% at doses from 10-80 mg daily, while raising high-density lipoprotein (HDL) cholesterol by 5-10% and lowering triglycerides by 20-40%. Clinical trials like the TNT study showed 80 mg daily reduced LDL to 77 mg/dL on average, cutting major cardiovascular events by 22% versus lower doses.[1][2]

Patients typically take it once daily, often at night, with effects visible in 2 weeks and maximum impact by 4-6 weeks. It's prescribed for high cholesterol, heart disease prevention, or post-heart attack management, alongside diet and exercise.[3]

Sources
[1]: FDA Label for Lipitor
[2]: NEJM: TNT Trial
[3]: DrugPatentWatch.com - Lipitor