Total cholesterol levels increase throughout a person's life. The two types of cholesterol are HDL, which is the good cholesterol, and LDL, which is the bad cholesterol. LDL levels also increase with age. There are many classes of medications that were developed to lower bad cholesterol and total cholesterol; the main target of almost all these medications is the LDL level.
Normal Levels
Cholesterol levels are measured during a routine blood test. Adults over the age of 20 should have their cholesterol levels measured every five years. According to "Pharmacotherapy: A Pathophysiologic Approach," the optimal level of LDL cholesterol is less than 100 mg/dL. A measurement between 100 and 120 mg/dL is above optimal, but not considered high. Levels between 130 and 159 mg/dL are considered borderline high. A level of 160 to 189 mg/dL is high, and anything over 190 mg/dL is considered very high.
Medications
The statins, or the HMG-CoA reductase inhibitors, are the class of drugs most effective at reducing LDL. The medications that belong to this class include lovastatin, atorvastatin, pitavastatin, fluvastatin, simvastatin, rosuvastatin and pravastatin. Niacin, a nicotinic acid, and ezetimibe are also effective in lowering LDL cholesterol. The bile acid-binding resins cholestyramine, colesevelam and colestipol may lower LDL, as well.
Action of Drugs
The statins block the actions of the enzyme HMG-CoA reductase. This leads to an increase the rate that LDL is broken down in the body, and increases the liver's removal of chemicals that form LDL. This leads to reduction in the amount of LDL in the blood. Niacin prevents the formation of LDL cholesterol. Ezetimibe blocks the absorption of cholesterol in the small intestine and leads to decreased delivery of cholesterol to the liver, reduction of liver cholesterol stores and increased elimination of cholesterol from the blood, explains the "Drug Information Handbook." The bile acid-binding resins bind to bile acids in the intestines and prevent their reabsorption. The bile, which is attached to LDL cholesterol, is eliminated from the body.
Fibric Acid Derivatives
Fibric acid derivates, which include gemfibrozil, fenofibrate and clofibrate, are not expected to significantly affect LDL levels. These medications are used to lower the triglyceride level. Only modest reductions of LDL cholesterol may occur with the fibric acids, states "Basic and Clinical Pharmacology." In some patients LDL may increase as triglycerides, which are the fat substances in the body, decrease.
Monitoring
Cholesterol levels should be assessed periodically, and drug therapy adjusted accordingly. Patients must also be monitored for adverse effects. The cholesterol-lowering medications cause gastrointestinal side effects, including nausea and vomiting. The statins, niacin, ezetimibe and the fibric acid derivative may affect liver function and require monitoring of liver function.
References
- "Drug Information Handbook"; Charles F. Lacy, Lora L. Armstrong, et al.; 2009
- "Drug Information Handbook"; Charles F. Lacy, Lora L. Armstrong, et al.; 2009
- "Basic and Clinical Pharmacology"; Bertram G. Katzung; 2007
