After years of understanding that high cholesterol levels can lead to atherosclerosis, and attempts to lower cholesterol by diet, exercise and medications, we are finally starting to have a pretty good understanding of how to lower cholesterol in patients with hypercholesterolemia.
First it is helpful to have a basic understanding of the types of cholesterol particles in our bloodstream. When we eat the nutrients we ingest are absorbed from the small intestine and go through capillaries and veins to the liver, using what is called the portal circulation. This nutrient rich blood is filtered through the liver where the fat we ingest is packaged with proteins into particles called lipoproteins ("lipo" for fat + "protein" for protein) Protein has a higher density than fat, and so particles made up of mostly cholesterol are called low density lipoproteins or LDL, and those made up of a higher concentration of protein, are high density lipoproteins or HDL. Although the full story is much more complex, in general it is good to have lots of HDL, and not much LDL.
As of this time we are not very good at helping patients increase their HDL cholesterol. Exercise, weight loss, and some medications like niacin can increase HDL modestly, but in general we do not have highly effective drugs to increase a person's HDL cholesterol.
LDL cholesterol is another matter. A class of medications called the "statins" which includes several generic and branded drugs, all work to inhibit the enzyme HMG-CoA Reductase. This enzyme plays a key role in the production of LDL cholesterol in the liver, and so by blocking its function much less LDL cholesterol is produced by the liver. Many studies have shown that use of statins to reduce LDL cholesterol can reduce second heart attacks in patients who have had a prior episode.
Most patients tolerate the statin class of medications well, but muscle pain is a fairly common side effect, and can lead to significant pain and weakness. In some patients use of pravastatin of red yeast rice which has small amounts of lovastatin produced naturally is tolerated when other statins cause unacceptable side effects.
The role of statins in primary prevention, i.e. patients without prior heart attacks, is not as well proven to be beneficial, but is still widely used in hopes of reducing cardiovascular risk.
Dr Pullen MD
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