Drug classification
The current application of Lipid regulating drugs are divided into the following categories
1. Statins such as lovastatin, simvastatin and so on.
2. Clofibrate and phenoxy acetic acid such as clofibrate, fenofibrate and gemfibrozil and so on.
3. Nicotinic acid and its derivatives such as nicotinic acid, inositol nicotinate and so on.
4. Cholic acid chelating agents such as cholestyramine and so on.

Mechanism of action
Atherosclerosis is mainly caused lipid metabolism disorder and decreased fibrinolytic activity, so adjustment of blood lipid metabolism can prevent and treat atherosclerosis. The lipid-regulating drugs have the following mechanisms.
1. The effect of statins is to inhibit the production of cholesterol in vivo.
2. Clofibrate class: its lipid-lowering effect is through increasing the activity of lipoprotein lipase and liver lipase activity so that triglyceride-rich protein catabolism can increase; it is capable of inhibiting the synthesis of cholesterol and triglyceride and the secretion of strerols. 
3. Niacin and its derivatives: its lipid-lowering effect may be through reducing the fat dissolution of adipose tissue, reducing the entering of free fatty acids into the liver, thus leading to the reduction of the formation of very low-density lipoprotein.
4. Cholic acid chelating agents can affect the absorption of cholesterol and cholic acid.

Clinical application
1. Statins can reduce the level of blood cholesterol and low-density lipoprotein levels with the reduction extent of 15% to 60%. It also has slightly weaker effect of lowering the blood triglycerides and increasing plasma high-density lipoprotein with the lipid-lowering effect being related to the dose.
2. Chlorpheniramine: its effect of lowering the blood triglyceride level is stronger than that of lowering the cholesterol level.
3. Niacin: it also has stronger effect on reducing the triglycerides than lowering the low-density lipoprotein of blood. It can also increase the blood high-density lipoprotein.
4. Cholic acid chelating agent can reduce blood levels of low-density lipoprotein and increase the high-density protein levels.