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Cholesterol-Reducing Drugs

 

Written by James Hannigan

 

Introduction

Most people are aware of the relationship between high cholesterol and increased risks of heart disease. High levels of cholesterol in the blood damages arteries throughout the body and can lead to heart attacks and strokes. Unfortunately, high cholesterol is a concern that many people have. Body Alive Health.com claims that more than half of American adults have hazardous blood cholesterol readings over 200 mg/dl and that as many as 36 million Americans should be taking cholesterol-lowering drugs. The following is an attempt to explain the issue surrounding high cholesterol and what solutions exist for those that suffer from it. (www.bodyalivehealth.com/products/cholestared.cfm)

 

The Problem with Cholesterol

 

What exactly is cholesterol? Kholesterol Blocker, a product designed to lower cholesterol levels, describes cholesterol as a "soft, waxy substance found among lipids in our bloodstream and in every cell of our bodies." (www.cholesterol-blocker.com/) Cholesterol comes from food but is also produced in the liver. The structure of cells, protection of the nervous system and production of hormones all require cholesterol. However, too much cholesterol in the blood can lead to blood vessel damage and possible heart attacks. When fatty substances, like cholesterol, combine in the bloodstream with a protein, they form lipoproteins. There are two types of cholesterol, high-density lipoprotein (HDL) and low density lipoprotein (LDL). HDL is considered ‘good cholesterol,’ it does not threaten people’s health like LDL does. LDL can build up on the walls of arteries forming plaque, which causes the arteries to become thicker, harder, less flexible, and eventually, restricts the blood flow to your heart and brain and increases your chances of having a heart attack or stroke. (www.merck.com/product/usa/zocor/cns/part3/zocor/home_zocor.html) (www.americanheart.org/Heart_and_Stroke_A_Z_Guide/)

The main factor for most people that contributes to their high level of cholesterol is a poor diet. Cholesterol is found in animal products, namely meat, poultry, seafood, and dairy products. A person whose diet is rich in these foods would be a threat for high cholesterol. In addition, medical problems such as poorly controlled diabetes, an underactive thyroid gland, an overactive pituitary gland, liver disease, kidney failure, and inherited disorders that prevent the body from properly using or eliminating fats can contribute to a person having a high level of cholesterol. (www.findarticles.com/cf_dls/g2601/0003/2601000315/print.jhtml )

Cholesterol levels can be tested through a blood test administered in a doctor’s office. In addition, if a patient has a history of heart disease in their family and is concerned with atherosclerosis, the build up of plaque in the arteries, they can have an angiogram taken. An angiogram essentially, is a picture of a person’s arteries. Doctors can analyze these pictures and pinpoint any possible blockages. At Northwestern University in Chicago, IL, scientists and doctors have come up with an alternative test for atherosclerosis called Nuclear Magnetic Resonance Spectroscopy. NMR uses radio waves to determine the size and concentration of lipoproteins in a patient’s bloodstream and is being used to conclude which patients would benefit most from specific cholesterol-reducing drugs. (http://www.vanderbilt.edu/AnS/psychology/health_psychology/healthpsych.HTM )

 

What Can Be Done?

 

 

According to the American Heart Association, for each one percent reduction in cholesterol, there is a two percent reduction in heart disease risk. Basically there are three ways to control cholesterol levels: improved diet, increased exercise, and medication.

 

Improved Diet

 

 

Simply checking the nutrition label on the back of food packages and limiting the amount of cholesterol and calories from fat consumed is a big step towards lowering one’s cholesterol. Fats provide energy for the body. The building blocks of fats are called fatty acids. These can be either saturated, monounsaturated, or poly-unsaturated. Saturated fats are usually found in animal products like red meats and eggs and they raise the level of cholesterol in the blood. Plant products generally contain unsaturated fats that do not contain cholesterol, so a diet that includes more whole grains, beans, seeds, vegetables, and fruits along with generally avoiding saturated fatty acids and foods that contain or are cooked in a lot of animal fat would reduce cholesterol.

 

Increased Exercise

 

 

Exercise is another great way to lower cholesterol. However, many people either lack the motivation to exercise regularly or are unsure what type of workout they should use. The best type of exercise, is aerobic exercise, where oxygen is used to provide energy to large muscles and to raise heart rates. Brisk walks or jogs are especially effective in combating cholesterol. As the American Heart Association reports, exercise helps to increase the HDL, or "good cholesterol" in one’s body and HDL has been reported to lower the level of LDL.

 

Medication

 

 

The third method of controlling cholesterol is to take cholesterol-reducing drugs. However, Dr. Joseph Mercola argues that diet and exercise is a sufficient therapy for most patients, but that many people with high cholesterol "prefer these ‘magic bullets’ to reduce their cholesterol because they do not want to make ANY lifestyle changes." (www.mercola.com/2000/may/21/cholesterol_drugs_expensive.htm) He believes that the only time cholesterol-reducing drugs are necessary are in cases of genetic liver problems. Nevertheless, there are three types of cholesterol reducing drugs: those that block cholesterol absorption, those that shut down the body’s production of cholesterol, and those that remove cholesterol from the bloodstream.

There is much uncertainty over the effects of taking cholesterol-reducing drugs both in the short-term and the long-term. As a result, clinical studies are constantly taking place that yield different claims about the risks of taking cholesterol-reducing drugs. Patients of any type of cholesterol-reduction therapy should pay attention to the new discoveries that regularly occur. While each of the three drug types differs in the way that they claim to lower cholesterol, they all share a few general side effects. According to the Gale Encyclopedia of Medicine, the most common side effects of cholesterol-reducing drugs include heartburn, indigestion, belching, nausea or vomiting, stomach pain, dizziness, headache, abdominal bloating, and gas. Fortunately, these effects usually pass as the body adjusts to the drug and do not require medical treatment. (www.findarticles.com/cf_dls/g2601/0003/2601000315/print.jhtml)

 

The following is a brief overview of the drugs that are available.

 

Plant Sterols

Description

The first type of drugs, those that block cholesterol absorption allow patients to maintain their current eating habits "without worrying about the cholesterol they’re consuming" (www.cholesterol-blocker.com/ ). Cholesterol (also know as animal sterol) comes from animal products while phytosterols (also known as plant sterols) come from plant products. There exists a certain plant sterol from soybeans whose molecular structure is very similar to the structure of the animal sterols that become cholesterol. It is the slight molecular difference however, that causes the animal sterols to enter the bloodstream and become converted into the lipoproteins that can clog arteries and the plant sterols to pass through the digestive tract. These cholesterol-reducing drugs take advantage of this slight difference. The body can not distinguish between the two and if the cholesterol receptor sites in the body’s digestive tract are given enough plant sterols during a meal, the receptor sites will not be able to absorb the animal sterols and most of the cholesterol will pass through the digestive tract. After failed attempts to enter the plant sterols into the blood stream, the cholesterol receptor sites eventually drop the plant sterols back into the digestive tract and they are eliminated. Essentially, these pills are highly concentrated plant sterols. When taken right before eating, they bombard the cholesterol receptor sites with plant sterols and occupy the receptors while the animal sterols slip by unnoticed. (www.cholesterol-blocker.com/)

Effectiveness

Kholesterol Blocker, a new drug produced by Nutrition for Life International, is one of the drugs that are designed to block cholesterol absorption by bombarding the cholesterol receptor sites in the digestive tract with plant sterols. At the top of their web page (www.cholesterol-blocker.com ) there is a picture of the product and next to that, in big letters are the following phrases: Completely Free of Side Effects! Helps Maintain Healthy Cholesterol Levels Naturally! Natural and Effective! Besides that, their website uses mainly testimonials to advertise the effectiveness of their product. The few stories that can be found tell tales of people whose cholesterol levels dropped significantly after using Kholesterol Blocker. One woman claims that in several months of therapy her cholesterol dropped from 388 to 218. The company does not use average figures to convince consumers to buy their product and their headlines, with the exception of declaring that there are no side effects, do not attempt to persuade consumers with outlandish claims.

Christiansen (2001) uses a study to prove the effectiveness of plant sterols in lowering LDL-cholesterol. During the study 155 58 year old (+/- 12 years) hypercholesterolemic subjects were split into groups and given different amounts or no phytosterols in the form of a spread enriched with microcrystalline plant sterols. After a 6 month experimental period, Christiansen found that on average the LDL-cholesterol concentrations had fallen by a margin of 7.5-11.6% from original levels in the groups that received the phytosterol spread. Christiansen did not however, find any change in HDL-cholesterol levels. Another study, performed by Maki and Davidson (2001), yielded similar results. In this particular study, all 224 subjects were put on a National Cholesterol Education Program Step I diet. In addition, 132 subjects were given plant-sterol-enriched spreads in varying amounts. 92 subjects received 1.1 gram of plant sterol esters per day and 40 subjects received 2.2 grams of plant sterol esters per day. After a 9 week experiment, Maki and Davidson found the subjects that actually consumed greater than 80% of the scheduled servings of plant sterol esters had lowered their total cholesterol level by 5.2% (6.6% in the 2.2 g/d group) and lowered their LDL-cholesterol levels by 7.6% (8.1% in 2.2 g/d group). These studies show that plant sterols are an effective way of lowering cholesterol levels whether taken by themselves or when dieting.

Safety

Despite Kholesterol Blocker’s insistence that its product is "completely free of side effects," many patients have experienced diarrhea while taking drugs that block cholesterol absorption. (Kholesterol Blocker). Furthermore, in analyzing the effects dietary phytosterol supplements have on intestinal microflora activity, Quilliot and Boman (2001) concluded that excessive amounts of phytosterols does cause diarrhea and can have an unfavourable effect on bacterial activity. Quilliot and Boman arrived at their conclusion by experimenting with 80 female Wistar rats that were fed an overly excessive amount of phytosterols over a 30 week long experiment.

However, both Christiansen (2001) and Maki and Davidson (2001) along with Nigon and Serfaty-Lacrosniere (2001) state that after analyzing the effects of plant sterol therapy, their subjects did not show any signs of adverse effects in blood chemistry, hematology, or vitamin concentrations, and that overall, the therapy was well tolerated.

 

Statins

Description

Very little information was found about how the second type of drugs, those that shut down the body’s production of cholesterol, work. They are called HMG CoA reductase inhibitors but are more commonly known as "statins" because the scientific names for these drugs all end in –statin (e.g., pravastatin, simvastatin, fluvastatin and lovastatin). They work by blocking the HMG CoA reductase enzyme in the body that produces cholesterol. In addition to blocking cholesterol synthesis, these drugs also enhance the liver’s ability to clear LDL cholesterol from the blood. (www.alpharx.com/AlphaRx/lipoblocer.html)

Effectiveness

Merck, the makers of Zocor (which is also known as simvastatin and is one of the drugs that blocks the enzyme in the body that produces cholesterol) uses multiple figures on their web page to prove the effectiveness of their product. Merck claims that based on their analysis of an experiment involving patients with high levels of cholesterol, the group that was given Zocor had 42% fewer deaths from heart disease, 34% fewer heart attacks, and 28% fewer first strokes or mini strokes than the group that received a placebo. In addition, Merck also provided the chart that is seen below. This chart lists the average changes in cholesterol in patients who used Zocor.

(www.merck.com/product/usa/zocor/cns/part3/zocor/home_zocor.html)

 

Most experts agree that HMG-CoA reductase inhibitors (statins) are affective in lowering total and LDL-cholesterol levels. The only disrepency is who should receive treatment and how much. Vogel and Schaefer (2001) examined whether statins were effective enough to be given to all patients with cardiovascular disease. They found that statins are generally regarded as safe, that administering the same drug to every CVD patient would be cost effective, and that statins have had a high rate of patient compliance in the past. They concluded however, that while statins do lower LDL-cholesterol levels, this is not the sole cause of atherosclerosis and that statin therapy would not reduce the risk of mortality in all cases.

Safety

HMG-CoA reductase inhibitors, or statins, which block the enzyme in the body that is needed to produce cholesterol, have been known to cause damage of the liver and muscles. (www.focusoncholesterol.com/script/main/art.asp?articlekey=12557) One specific statin, Baycol (cerivastatin), has been removed from the U.S. market by its producer, Bayer Pharmaceutical Division because of reports that the drug has caused a severe muscle adverse reaction in some drug users known as rhabdomyolysis. Baycol has been linked by the FDA to the deaths of 31 Americans as a result of rhabdomyolysis, a condition where muscle cells are broken down and their contents are released into the bloodstream of patients causing them severe muscular pain, weakness, fever, and nausea. (www.baycol-facts.com/news_fda8-8-01.htm)

In addition, many people believe that the use of statins over a long period of time results in either cancer, cataracts, or hepatotoxicity. There exists however research that disputes each one of these beliefs.

Bjerre and LeLorier (2001) attacked the long term carcinogenicity myth by analyzing statin therapy studies from January 1966 to December 1999. Bjerre and LeLorier used the Medline Database to find these studies. To ensure that their results were conclusive, they only used studies where treatment lasted for at least 4 years and at least 1,000 subjects were included. Bjerre and LeLorier chose 5 studies, and then explored the cancer history of those subjects and concluded that there is no association between statin use over a 5 year period and the risk of cancer.

Similarly, Schlienger, Haefeli, Jick, and Meier (2001) conducted an analysis of all cataract cases in the United Kingdom-based General Practice Research Database and investigated possible links between using statins. Of the 35,732 cataract cases they investigated, only 7,405 had used statins previous to their diagnosis. According to Schlienger, Haefeli, Jick, and Meier, this is an appropriate ratio and that there is no correlation between long term statin use and increased risk of developing cataract.

Tolman (2000) dealt with the hepatotoxicity concern. Hepatotoxicity can lead to cholestasis, jaundice, hepatitis, chronic active hepatitis, fatty liver, cirrhosis, and acute liver failure. Tolman's report explains that hepatotoxicity is a rare reaction, that there are case reports associated with all cholesterol-reduction therapies, and that long term statin use does not change a patients chances of hepatotoxicity.

 

Bile Acid Sequestrants

Description

The third type of drugs, those that remove cholesterol from the bloodstream are different from the others. As opposed to the first two types of drugs, which are considered absorbed cholesterol-reducing drugs because they deal with the absorption of cholesterol into the bloodstream; these drugs are known as non-absorbed agents because they take an alternative approach to lowering cholesterol levels. More specifically, these drugs are called bile acid sequestrants. Bile acid is a product synthesized from cholesterol by the liver and secreted into the intestines to aid digestion of fats. These bile acid sequestrants bind to the bile acid in the intestinal tract and increase the excretion of bile acid from the body. To counteract the loss of bile acid, the liver takes more cholesterol from the bloodstream and produces more bile acid, thus lowering the amount of cholesterol present in the bloodstream. (www.alpharx.com/AlphaRx/lipoblocer.html)

Effectiveness

Unfortunately, there does not seem to exist a web page devoted to advertising Questran, Colestid, or any other bile acid sequestrant (the third type of cholesterol-reduction drug). As opposed to consumer testimonials proclaiming miraculous changes in cholesterol levels, the only product descriptions found were on online pharmacies in brief paragraphs. The claims there were hardly controversial or exaggerated. Nevertheless, Pharmacia Online has copies of the drug description, recommended dosages, and hazards that are given to consumers upon purchase of Colestid. (www.colestid.com/products/pharmaciaproducts-rx/colesgr.pdf ) Similarly, Hepatitis Central has a web page that has an in depth description of how Questran works, the different physical forms the medication comes in, any precautions patients should take while on the medication, and a list of any possible side effects they may encounter. (http://hepatitis-central.com/hcv/drugs/questran.html)

Regardless of the lack of advertising, Farmer and Gotto (1996) report, "the agents with the greatest LDL cholesterol-lowering effect are the bile acid sequestrants." According to a study outlined in Gaw (1996), bile acid sequestrant therapy, specifically colestipol, has been proven to lower total cholesterol by 14% and LDL-cholesterol by 23%. This study was conducted on a group of 8 males with moderate hypercholesterolemia who had undergone coronary artery bypass grafting more than 3 months prior. These men were told not to alter their diet and to take regular doses of colestipol. After the experimental period, while the group's LDL-cholesterol had fallen dramatically, HDL-cholesterol and triglyceride levels remained the same. A similar study reported in Aldridge and Ito (2001) reported that after being administered between 3.75 and 4.5 grams per day of colesevelam, a bile acid sequestrant similar to colestipol, subjects showed a mean LDL-cholesterol decrease of 20% and HDL-cholesterol increase of 9%.

Safety

The only reported danger of using bile acid sequestrants was that according to the Natural Health Encyclopedia at the Personal Health Zone, these drugs have been reported to impair the body’s ability to absorb nutrients, namely calcium, folate, iron, and vitamins A, B12, and K. (www.personalhealthzone.com/pg000345.html)

In addition, while there are fewer complaints of constipation with the newer bile acid sequestrants that come in different forms to increase compliance, a 65-year old man who had been receiving colestipol for 3 months developed asymptomatic hepatotoxicity and his liver began to malfunction. After discontinuing colestipol treatment, all liver functions returned to normal. Sirmans, Beck, Banh, and Freeman (2001) More research is being done on the adverse effects of colestipol on a patient's liver but colestipol patients may require liver function monitoring.

 

Conclusion

After much research, it is clear that there is not one simple solution for high cholesterol. For many people, controlling high levels of cholesterol is a long struggle that involves trying many different types of therapies in order to find out which one strategy works best for them. It is important that cholesterol-reducing drugs are not viewed as "magic bullets" that allows patients to avoid making lifestyle changes (as Dr. Mercola feared), because while cholesterol-reducing drugs do help people control their cholesterol levels, they do not cure the problems that cause high cholesterol such as a poor diet or lack of exercise.

 

References

 

 

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