About cholesterol-lowering drugs
Cholesterol-reducing drugs are medications that lower the levels of fats (lipids) in the blood, including cholesterol and triglycerides. Besides lowering total cholesterol and LDL (“bad”) cholesterol levels, some cholesterol-lowering medications may also modestly increase levels of HDL (“good”) cholesterol. High LDL cholesterol levels and low HDL cholesterol levels are associated with heart attack, stroke and coronary artery disease.
Cholesterol-reducing drugs work on lipids in the bloodstream. Some work by reducing the amount of cholesterol or triglycerides produced or absorbed in the body. Others remove cholesterol that has built up in the arteries. The mechanisms and strengths of each type of cholesterol-reducing drug varies.
In general, cholesterol is a waxy type of fat that is produced naturally by the body and consumed in relatively modest amounts through the diet. Cholesterol is important because it is used as a building block for hormones, such as estrogen and testosterone. Cholesterol itself is carried through the bloodstream in a package known as a lipoprotein. Researchers have identified a number of different lipoproteins, each of which interacts with the body in a different way. High-density lipoproteins, or HDLs, are compact packages that can remove cholesterol from arteries, thus reducing the risk of heart attack and stroke. Other types of lipoproteins, including low-density lipoproteins (LDL), very low-density lipoproteins (VLDL) and intermediate density lipoproteins, are unstable packages that can deposit cholesterol into an artery, thus accelerating atherosclerosis and raising the risk of heart attack and stroke. triglycerides are another type of fat that are associated with increased cardiovascular risk.
The point of cholesterol-lowering medications is to favorably affect the lipid profile, or relative levels of HDL and LDL cholesterol in the bloodstream. Studies have shown that patients who have very high HDL levels experience a protective effect, while patients with elevated LDLs are at increased risk. Thus, cholesterol-lowering medications are routinely used to affect a person's coronary risk profile. They may be prescribed by people who have already experienced a heart attack or stroke, who have undergone a catheter-based therapy such as angioplasty with or without stenting, bypass surgery, or even patients who are at risk of dangerous arrhythmias.
Types and differences of cholesterol-reducing drugs
Different types of cholesterol reducers affect levels of fats (lipids) in different ways and generally fall into the following categories:
StatinsConsidered the first line of treatment for most patients with high cholesterol (hypercholesterolemia), statins block the production of specific enzymes used by the body to make cholesterol. Statins have been shown to reduce the risk of a first heart attack, as well as recurrent heart attacks in patients with known disease, and stroke. They have also been shown to reduce the risk of death among patients with heart failure. Statins are particularly effective at lowering levels of LDL (“bad”) cholesterol and, to a lesser degree, triglycerides. While statins do increase levels of HDL (“good”) cholesterol, they do not seem to increase those levels as well as other cholesterol reducers do. Statins generally have limited side effects, although there are some reports of a rare muscle deterioration called rhabdomyolysis. Some media reports have also linked statins to reduced memory function, but this appears to be a rare side effect. Periodic blood testing is advisable to monitor both the side effects on blood fats and to monitor liver function.
The decision to administer statins depends on multiple clinical considerations including the total cholesterol levels, LDL levels, HDL levels, history of previous myocardial infarction and other risk factors for coronary artery disease, particularly diabetes. Statins have been shown to have a favorable effect on the arteries irrespective of the degree of cholesterol lowering achieved. This effect is believed to be through an anti-inflammatory action resulting in stabilization of atherosclerotic plaque. Because of this, some studies have suggested that intensive, immediate statin therapy may be initiated for patients who are hospitalized with coronary artery disease.
Bile acid resinsBecause the liver takes cholesterol out of the blood to make bile, bile acid resins prevent the recycling of bile acids in the intestine. As a result, the liver is forced to remove more cholesterol from the blood in order to manufacture more bile. Bile acid resins are usually taken in powder form or in a chewable bar. Many patients, however, have gastrointestinal discomfort with these drugs. Bile acid resins are also known to bind to other substances, such as fat-soluble vitamins, the heart drug digoxin and the anticoagulant warfarin. It is not recommended that patients take these drugs at the same time they are taking bile acid resins.
Nicotinic acid (a form of vitamin B3)In large doses, nicotinic acid is very effective in lowering triglyceride levels and raising levels of HDL (“good”) cholesterol. Nicotinic acid can also lower levels of LDL (“bad”) cholesterol, but not as effectively as other cholesterol reducers. When taking niacin, patients are advised to slowly build up to the high doses needed to treat high cholesterol. Taking too much niacin can lead to intense side effects that include flushing, palpitations, nausea and, in extreme cases, liver toxicity (especially when taken in “rapid-release” form). Even with proper build-up, as many as 50 percent of patients find the side effects of this medication too difficult to tolerate. Nicotinic acid is available over the counter, but physicians prefer to prescribe it in time-released pills. Because of the potentially intense side effects, patients should never begin taking niacin without the supervision of a physician. Additionally, many of the "no flush" niacin dietary supplements sold over the counter do not affect blood lipid levels.
Fibrates (or fibric acid derivatives)Fibric acid reduces the production of triglycerides and increases the rate at which existing triglycerides are removed from the bloodstream. Fibrates can significantly lower triglyceride levels and modestly increase HDL (“good”) cholesterol levels in most patients, but they are less effective at reducing LDL (“bad”) cholesterol levels. They are most commonly used in patients who have elevated triglyceride levels, usually in conjunction with low HDLs (many diabetics have this type of lipid profile). Simultaneous use of fibrates and statins should be carefully monitored.
EzetimibeEzetimibe is a newer class of cholesterol drug that blocks cholesterol absorption in the small intestine. It has been shown to reduce LDL cholesterol levels, although not as much as statins. Ezetimibe has been marketed alone and combined with statin drugs. The drug class was approved by the U.S. Food and Drug Administration in 2004, but a clinical study released in 2008 indicated that ezetimibe alone or in combination provided no benefits that could not be achieved with a statin drug. One specific measure in the study (the thickness of plaques in carotid arteries) did not improve at all and, in some cases, appeared worsened by the drug.
Examples of these medications* include the following:
Statins Bile acid resins Nicotinic acid Fibrates
Niacin (vitamin B3)
Investigations continue with a new medication that influences HDL levels. Known as a CETP inhibitor, the drug is thought to block a particular protein responsible for lowering HDL. A recent study of torcetrapib, a CETP inhibitor, in combination with a statin unexpectedly showed an increase in deaths and cardiovascular events compared to a statin alone.
- Side effects
Potential side effects of cholesterol drugs
There are a number of side effects that could occur as a result of taking cholesterol reducers, but fortunately, side effect frequency is low. Muscle aches can occur with statin use and must be immediately reported to a physician. Certain cholesterol-lowering medications can also produce abnormal liver function in approximately 2 percent of the population, which can be diagnosed by periodic liver enzyme testing. In rare cases, this may lead to liver failure. Patients with moderate or severe liver disease should not take statins. For the most part, abnormal liver function is reversible when the statin is discontinued.
A rare, but potentially fatal side effect of some cholesterol-reducing drugs (statins and certain fibrates) is rhabdomyolysis, a severe muscle reaction in which muscle cells break down, releasing their contents into the bloodstream. Physicians can monitor patients for this complication by checking muscle enzyme levels (e.g., creatine phosphokinase [CPK]) in the blood. It most often affects the muscles in the back or lower calves. Some patients report no symptoms and in rare cases rhabdomyolysis can lead to kidney or other organ failure and death. Patients should report any of the following symptoms of rhabdomyolysis to their physicians immediately:
- Muscle cramps, pain, swelling, weakness, stiffness and/or tenderness
- Dark urine
- Nausea and/or vomiting
- Malaise (a general feeling of illness or discomfort)
Risk of this severe complication appears to be higher in elderly patients, those taking high doses of statin and those taking statins in conjunction with a fibrate (e.g., fenofibrate, gemfibrozil). In 2001, one type of statin, called cerivastatin (brand name “Baycol”) was voluntarily withdrawn from the market by its manufacturer due to reports that fatal cases of rhabdomyolysis had been significantly more common with cerivastatin than with other approved statin drugs.
Statins carry a very low risk of side effects to the nervous system, including tingling, numbness and burning pain. These manifestations are known as peripheral neuropathy.
Patients on any cholesterol-lowering drugs should also notify their physician if they experience any side effects such as the following:
- Allergic reaction (new onset of wheezing, respiratory congestion, itching or skin rashes)
- Abdominal pain
- Dizziness or lightheadedness
- Flushing of the face or neck
- Blurred vision
- Drowsiness, weakness or fatigue
- Nausea or vomiting
- Hair loss
- Decreased sexual interest or ability
Drug or other interactions
Patients should consult their physician before taking any other medication (either prescription or over-the-counter) or nutritional supplements. Of particular concern to patients taking cholesterol reducers are other cholesterol reducers. Taking more than one cholesterol reducer at a time may worsen side effects, unless physicians have prescribed a specially dosed combination of medications.
It is also important to consider the effects of over-the-counter herbal remedies that claim to lower cholesterol. Because these preparations do not make explicit health claims, they do not undergo the same level of scrutiny by the U.S. Food and Drug Administration as do prescription drugs. For example, the herbal remedy “guggul,” derived from the mukul myrhh tree, has been advertised as a “cholesterol-fighter.” However, researchers found, however, that it actually increased levels of LDL (“bad”) cholesterol.
Other substances that may cause concern for some types of cholesterol-reducing drugs include:
- Inotropes (e.g., digoxin)
- Birth control pills
- Calcium channel blockers
- Protease inhibitors (for treatment of human immunodeficiency virus, HIV)
- Azole antifungals (systemic antifungals)
- Immunosuppressants (reduce the body's immune system)
- Some antibiotics
- Antihypertensives (medications to treat high blood pressure)
- Diuretics (water pills)
- Certain NSAIDs (nonsteroidal anti–inflammatory drugs)
- Certain beta blockers
- Thyroid hormones
Patients taking cholesterol-reducing drugs may also be instructed to avoid grapefruit juice. Grapefruit juice interferes with the liver’s ability to rid the body of some substances. This could lead to a buildup of medications to toxic levels in the body. While the buildup is less likely if the juice is ingested four or more hours prior to the medicine, patients taking cholesterol reducers are usually advised to refrain from drinking grapefruit juice. Patients may also be instructed to avoid eating grapefruit.
Lifestyle considerations with Cholesterol Blocker
Some cholesterol reducers can cause liver inflammation, which tends to resolve on its own after patients stop taking the medication. To monitor this and other complications, patients will undergo regular blood tests and liver function tests.
Women taking cholesterol-reducing drugs should inform their physicians at once if they are or plan to become pregnant. Although it has been found that statins do not have a negative effect on female reproductive hormone levels, cholesterol is an important contributor to the development of the fetus. In addition, some cholesterol reducers are excreted in breastmilk. Nursing mothers, therefore, should consult with their physician before taking or discontinuing these drugs. Patients should not abruptly stop taking their medications without first consulting their physicians. It is also important that patients notify all physicians (including dentists) that they are taking statins before undergoing any surgical procedure. And all patients taking statins should inform their physician immediately of any side effects or concerns.
Most patients on medication to treat high cholesterol (hypercholesterolemia) will be taking it for the rest of their lives, provided no serious side effects occur. Patients should remember that medications may control high cholesterol, but they do not cure it. Even if all their symptoms are relieved, patients should continue to take their medication exactly as directed, eat a heart-healthy diet that is low in saturated fats and keep all scheduled follow-up appointments with their physician. Numerous studies have shown the dangers associated with noncompliance, or people not taking their cholesterol-lowering medications exactly as prescribed. Even if the medications do not appear to make you "feel better," there is a significantly higher risk of heart attack among people who simply stop taking their medications.
Questions for your doctorPatients may wish to ask their doctors the following questions related to cholesterol-reducing drugs:
- Do I need cholesterol-reducing medication? Why?
- Can weight loss and dietary changes eliminate the need for this medication?
- What type of cholesterol-reducing drug should I take?
- Will I have to take this medication daily or only under certain conditions?
- Does one type of this medication have more side effects than others?
- If one type of this medicine does not help my cholesterol level, will other types work?
- Does everyone experience side effects? Which one should I report?
- Are newer cholesterol drugs better than older ones?
- Is it more important for a medicine to work on my cholesterol or triglyceride levels?
- I know lifestyle and diet changes can help lower my LDL cholesterol. Are there any changes that can help raise my HDL cholesterol?