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Lowering LDL Cholesterol: Bile Acid Sequestrants
The next group of Gastrointestinally Active Lipid Lowering Drugs I will talk about are the Bile Acid Sequestrants (BASs). Like Zetia, this class of drugs works in the intestines. They have been used since the 1960s. Since they are not absorbed into the body they are inherently safe and also safe during pregnancy.
They are a good class of drugs for young adults contemplating a potential lifetime of exposure to a medication and are the only class of drugs recommended by NCEP for use in children. The three most common adverse events that have been reported are constipation, rarely leading to obstruction, increase in plasma triglyceride levels, and decrease absorption of some medicines and certain vitamins. The newest agent, Colesevelam (Welchol)-available as a tablet, has greater affinity for bile acids compared with the older medicines such as Cholestyramine(Questran)-available as a powder, so it has fewer drug interactions and is less likely to cause constipation.
The main problem with this class of drugs for patients with hypercholesterolemia can be the taste, the amount that needs to be taken, and the bloating and constipation. I tell my patients to take a stool softener while on this class of drugs or to drink prune juice. Since the development of Welchol and the improved gastrointestinal tolerance, more patients are willing to take BASs. In an analysis of 3 randomized, placebo-controlled trials of Welchol added to statin therapy, constipation was only reported in less than 10% of patients and less than 5% withdrew secondary to side effects.
These classes of drugs are anion-exchangers and cause increased clearance of LDL-C from the blood. As I said previously, they work in the intestines by binding bile acids, and thus, interrupt the circulation of bile acids back to the liver. Since there is less bile acid available, cholesterol is converted to bile acid and the concentration of cholesterol within the liver falls. As this happens, LDL receptor activity of the liver cell increases which then increases LDL clearance from the blood.
The largest set of data on Bile Acid Sequestrants comes from the Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT). Reduction in coronary risk corresponded to LDL-C reduction. When the maximum dose of 24 grams/day of Cholestyramine was used, there was 28% reduction in LDL-C and a 39% reduction in CHD risk. The BASs have been used alone or in combination with other lipid lowering medications in one major trial with a clinical endpoint and in five with angiographic endpoints.
BASs should be avoided in patients with TGs greater than 400mg/dl because they tend to raise TG levels. If it is be used in combination with medicines to lower TGs, this is not a major concern but if used alone should only be used if one's TG level is less than 200mg/dl.
Finally, due to potential drug interactions, coumadin, thiazide diuretics, propanolol, tetracycline, penicillin G, phenobarbital, thyroid preparations, estrogens, progestins, and digoxin should be administered one hour before or four hours after taking the older BAS agents. The current evidence has shown that Welchol can be taken concurrently with these medicines. The next class of drugs we will explore in the coming weeks will be fibrates.
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They are a good class of drugs for young adults contemplating a potential lifetime of exposure to a medication and are the only class of drugs recommended by NCEP for use in children. The three most common adverse events that have been reported are constipation, rarely leading to obstruction, increase in plasma triglyceride levels, and decrease absorption of some medicines and certain vitamins. The newest agent, Colesevelam (Welchol)-available as a tablet, has greater affinity for bile acids compared with the older medicines such as Cholestyramine(Questran)-available as a powder, so it has fewer drug interactions and is less likely to cause constipation.
The main problem with this class of drugs for patients with hypercholesterolemia can be the taste, the amount that needs to be taken, and the bloating and constipation. I tell my patients to take a stool softener while on this class of drugs or to drink prune juice. Since the development of Welchol and the improved gastrointestinal tolerance, more patients are willing to take BASs. In an analysis of 3 randomized, placebo-controlled trials of Welchol added to statin therapy, constipation was only reported in less than 10% of patients and less than 5% withdrew secondary to side effects.
These classes of drugs are anion-exchangers and cause increased clearance of LDL-C from the blood. As I said previously, they work in the intestines by binding bile acids, and thus, interrupt the circulation of bile acids back to the liver. Since there is less bile acid available, cholesterol is converted to bile acid and the concentration of cholesterol within the liver falls. As this happens, LDL receptor activity of the liver cell increases which then increases LDL clearance from the blood.
The largest set of data on Bile Acid Sequestrants comes from the Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT). Reduction in coronary risk corresponded to LDL-C reduction. When the maximum dose of 24 grams/day of Cholestyramine was used, there was 28% reduction in LDL-C and a 39% reduction in CHD risk. The BASs have been used alone or in combination with other lipid lowering medications in one major trial with a clinical endpoint and in five with angiographic endpoints.
BASs should be avoided in patients with TGs greater than 400mg/dl because they tend to raise TG levels. If it is be used in combination with medicines to lower TGs, this is not a major concern but if used alone should only be used if one's TG level is less than 200mg/dl.
Finally, due to potential drug interactions, coumadin, thiazide diuretics, propanolol, tetracycline, penicillin G, phenobarbital, thyroid preparations, estrogens, progestins, and digoxin should be administered one hour before or four hours after taking the older BAS agents. The current evidence has shown that Welchol can be taken concurrently with these medicines. The next class of drugs we will explore in the coming weeks will be fibrates.
Related Topics:
5 Comments:
My brother has high cholesterol and I've been begging him to be more aware of his diet and his health (but would he listen to his younger sister?) I've never heard of the bile acid sequestrants but I think it is very interesting and hopefully my brother will appreciate it. As of now, I had read a study in the American Journal of Clinical Nutrition that immunized skim milk can help lower cholesterol and even blood pressure. So I have been sending him orders of immunized milk supplements through the mail, hoping he will listen to me and mix it into his morning coffee or cereal or something, but I will definitely share this article with him tonight. Thank you!
Thank you very much for your kind words. I think the BASs would be a good starting point for your brother. Remember that CV disease is the #1 killer of Americans and Atherosclerosis is the most modifiable risk factor. He needs to start treating his high cholesterol at a young age beginning with total lifestyle changes and then using meds under the guidance of a qualified physician if deemed necessary.
I was on Zetia for 6 months -- I got excrusiating leg cramps in both legs and could barely walk! Went to my Dr. & argued with him about Zetia as the cause! Took myself off & it took 10 weeks before the pain subsided; and it's been 11 months and I'm still having pain in my legs & arms & muscles! After 3 doctors and now at Jefferson in Phila. they agree I have muscle damage. Do not recommend cholestrol medications as they can do real damage to your muscles! Jean
I have been taking Cholestyramine Oral for approx. 5 years for Irratible Bowel Syndrome (IBS) It literally saved my life! I was having severe diarrea for years and my docter "thought out of the box" to find some way to stop this. I take 1/2 packet every other day. PS. NOT for high cholestrol but to stop diarrea.
Zetia enters the bloodstream and therefore is more likely to have side-effects such as muscle aches. Watch their commercials, they say your Dr. may want to run liver tests before prescribing Zetia, this means it enters your bloodstream. BAS's such as Welchol do not enter the bloodstream and therefore do not travel to your muscles. No liver tests are required. The main side effects are gastro related as it works strictly in the intestine.
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