The main ingredient of Lipitor is atorvastatin calcium, which is the original dosage form of the drug. Lipitor works by causing a decrease in LDL cholesterol. The relatively common side effects are an increase in transaminases, and muscle damage. Lipitor can lower LDL cholesterol and triglycerides and raise HDL by inhibiting cholesterol synthesis. By reducing these effects, Lipitor protects the arteries and reduces the risk of atherosclerosis, which is important for the prevention of heart attacks and brain attacks. The safety and tolerability of Lipitor are relatively good, and the occurrence of adverse effects does not correlate with the dose of the drug. Only 0.7% of patients taking Lipitor experience persistent transaminase elevations that are more than three times the normal value. Side effects occur within 16 weeks after treatment, with occasional myopathy.