From the FDA Drug Label
Atorvastatin is a selective, competitive inhibitor of HMG-CoA reductase, the rate-limiting enzyme that converts 3-hydroxy-3-methylglutaryl-coenzyme A to mevalonate, a precursor of sterols, including cholesterol In animal models, atorvastatin calcium lowers plasma cholesterol and lipoprotein levels by inhibiting HMG-CoA reductase and cholesterol synthesis in the liver and by increasing the number of hepatic LDL receptors on the cell surface to enhance uptake and catabolism of LDL; atorvastatin calcium also reduces LDL production and the number of LDL particles.
Lipitor (atorvastatin) works by inhibiting the enzyme HMG-CoA reductase, which is involved in the production of cholesterol in the liver. This inhibition leads to a decrease in the production of LDL (bad) cholesterol and an increase in the removal of LDL cholesterol from the bloodstream. The main mechanisms of action are:
- Inhibition of HMG-CoA reductase
- Reduction of cholesterol synthesis in the liver
- Increase in the number of hepatic LDL receptors
- Enhancement of LDL uptake and catabolism
- Reduction of LDL production and the number of LDL particles 1
From the Research
Lipitor (atorvastatin) works by reducing cholesterol production in the liver through the inhibition of the HMG-CoA reductase enzyme, which is essential for cholesterol synthesis, as supported by the most recent and highest quality study 2.
Mechanism of Action
The medication specifically blocks the HMG-CoA reductase enzyme, leading to a decrease in the amount of LDL ("bad") cholesterol and triglycerides in the bloodstream, while slightly increasing HDL ("good") cholesterol levels. This action is a result of the up-regulation of LDL receptors in the liver, which increases the clearance of LDL-cholesterol from the plasma 2.
Dosage and Administration
Typical dosing ranges from 10-80 mg once daily, with 10 or 20 mg being common starting doses. The medication is most effective when taken consistently at the same time each day, usually in the evening, and works best alongside dietary changes and exercise.
Efficacy and Safety
Patients should know that Lipitor may take 2-4 weeks to show initial effects, with maximum benefit occurring after 4-6 weeks of regular use. Side effects can include muscle pain, liver enzyme elevations, and digestive issues. However, atorvastatin has been shown to be well-tolerated, with adverse events usually being mild and transient 3.
Clinical Benefits
Lipitor belongs to the statin class of medications, which have been shown to significantly reduce the risk of heart attacks and strokes in patients with elevated cholesterol levels or existing cardiovascular disease. The medication's ability to reduce LDL-cholesterol levels has been demonstrated to substantially lower cardiovascular event rates in high-risk patients 2.
Some key points to consider when prescribing Lipitor include:
- The medication's efficacy in reducing LDL-cholesterol levels and its ability to meet recommended treatment guidelines
- Its effect on triglyceride levels and capacity to modify lipoprotein composition in a non-atherogenic manner
- The importance of achieving maximal reduction of LDL-cholesterol in at-risk patients to reduce cardiovascular event rates
- The potential for pleiotropic effects, including antiatherosclerotic effects independently of hypolipidemic action, and beneficial effects on bone formation and tumor cell growth 4.