High cholesterol is one of a number of risk factors for developing heart disease, which is the number one cause of death among Americans in 2010. Cholesterol levels may be lowered by making certain lifestyle changes, such as engaging in more physical activity and eating healthier. If these changes fail to produce an optimal cholesterol level, your doctor may prescribe a cholesterol-lowering medication. The first-line agents are the statins. However, there are other types of medications that will also effectively lower your cholesterol.
In addition to statins, your doctor may select a medication from the other four types of cholesterol-lowering medications. These are the fibrates, bile acid sequestrants, intestinal absorption blockers and niacin. These agents work in different ways and may be used alone or added to a statin for a synergistic effect. Examples of fibrates are fenofibrate (Tricor) and gemfibrozil (Lopid). Cholestyramine (Questran), colestipol (Colestid) and colesevelam (Welchol) are examples of bile acid sequestrants. The only intestinal absorption blocker currently on the market as of 2010 is ezetimibe (Zetia). Niacin or nicotinic acid is a B vitamin and is available over the counter. It's also available as an extended-release prescription formulation called Niaspan.
Mechanism of Action
Each class of cholesterol-lowering medication works in a different way. The bile acid sequestrants work by binding to bile acids in the intestine, resulting in their elimination from your body. Bile acids are necessary for the formation of cholesterol. The fibrates work by decreasing the formation of VLDL, very low-density lipoproteins. This type of cholesterol particle carries fat in the blood called triglycerides. Nicotinic acid works by blocking the formation of LDL, the bad cholesterol, and decreasing the production of VLDL in the liver. Ezetimibe works by blocking the absorption of dietary cholesterol in the intestine.
By far, the statins are the most effective at lowering LDL, which is the primary target of treatment. They lower LDL by 18 to 55 percent. The non-statin cholesterol-lowering medications are also effective at lowering LDL but to a lesser extent. The bile-acid sequestrants decrease LDL by 15 to 30 percent of baseline numbers. They are useful alone or in combination with statins. In combination, the LDL lowering effect increases by 12 to 16 percent. Bile acid sequestrants favorably affect the good cholesterol, HDL. They increase it by 3 to 5 percent. Fibrates decrease LDL by 5 to 20 percent. They are most effective for lowering triglycerides (TG). They decrease them by 20 to 50 percent and at the same time, increase HDL by 10 to 35 percent. Nicotinic acid affects LDL, HDL and triglyceride levels. Like the fibrates, it lowers TG by 20 to 50 percent. It raises HDL to a greater degree--15 to 35 percent--and decreases LDL by 5 to 25 percent.
Just as these agents differ in their effectiveness, they also differ in their side effect profiles. Bile acid sequestrants cause constipation, abdominal pain, bloating and gas. Fibrates may potentially cause indigestion, headache, muscle weakness and/or pain. They may also cause liver damage, especially when combined with a statin. Nicotinic acid causes flushing, itching, rash and high blood sugar. The sustained-release formulations increase your risk for developing liver damage. Ezetimibe may cause muscle pain and abdominal pain.
When treating your cholesterol, you doctor will consider your LDL baseline number as well as any other health conditions you have, such as diabetes, liver disease or existing heart disease. These conditions will help him choose the best medication for you.