The difference between simvastatin and atorvastatin calcium tablets is the mechanism of action of the drugs and the time to effect. 1. Simvastatin belongs to the inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, which can inhibit the synthesis of endogenous cholesterol after taking it, thus lowering the level of LDL cholesterol. It is mainly used in the treatment of hypercholesterolemia and coronary heart disease. Secondly, it takes about 4 hours for the drug to reach its peak concentration after taking it, and the effect is maintained in the body for about 12 hours. It may also cause discomfort such as abdominal pain and muscle cramps. It is contraindicated in people with active liver disease. Pregnant and lactating women should use the drug under medical supervision. 2. Atorvastatin Calcium Tablet is a selective and competitive inhibitor of HMG-CoA reductase, which can inhibit cholesterol synthesis and reduce plasma cholesterol and lipoprotein levels, and is mainly used in the treatment of hypercholesterolemia and coronary heart disease. The drug can reach the peak concentration of the drug in about 1~2 hours after taking it, so as to exert the effect of the drug, and can also maintain the effect of the drug in the body for 14 hours. The drug is contraindicated in people with active liver disease and allergy to the components of the drug. It may also cause skeletal muscle pain and other discomforts. Secondly, it is necessary to monitor liver function, kidney function and regular review of serum lipids during the course of taking the drug. Pregnant and lactating women should use the drug under the guidance of a doctor. To summarize, the difference between the above two drugs lies in the time for the drug to take effect and the mechanism of action of the drug. If you need to take the above medication, it is recommended to use the medication under the guidance of a doctor, not blindly use their own medication to avoid adverse effects.