A active agent
The active agent of a drug drug is the chemical substance that causes the effect, and it often differs from the drug's brand name. For example the name of a popular cholesterol-lowerifng drug is Lipitor? manufactured by Pfizer, but the name of the active agent in Lipitor? is atorvastatin. Generic drugs which are generally cheaper than the original drugs are often named after the active agent such as "Simvastatin Tablets" by IVAX Pharmaceuticals (original drug: Zocor? by Merck & Co.).
aneurysmBlood-filled widening of a blood vessel or the heart. Sometimes the large body artery or aorta coming from the heart is affected. Tearing of the damaged and thinned aorta wall can lead to catastrophic internal bleeding.
Origin: Greek "aneurysma" = widening.
Chest pain caused by insufficient supply of oxygen to the heart muscle. The underlaying cause is often a narrowing of the arteries by atherosclerosis that causes acute problems during times of physical or psychological stress when more oxygen is required.
Proteins that form the outer shell of lipoproteins are called apolipoproteins or apo for short. Apolipoproteins contribute by making lipoproteins water-soluble so that cholesterol and triglycerides can be transported in the arteries. Each lipoprotein type has a specific subset of apoproteins such as HDL particles that carry mainly apolipoprotein A and LDL which carries predominantly apolipoprotein B100. Cells can discriminate between each type of lipoprotein particle by reading this "bar code" of lipoproteins with special receptors.
Arteries are the blood vessels that deliver blood from the heart to the body, opposed to the veins that return blood from the body to the heart. Blood pressure is always measured for the arteries, where approximately 120 mmHg ("systolic" - when the heart beats) over 80 mmHg ("diastolic" - in-between two heart beats) is considered normal. The abbreviation mmHg stands for "millimeter of mercury" and dates back to a time when mercury-filled tubes were used for pressure measurements.
Origin: Greek "hardening of the arteries" The term arteriosclerosis describes the general phenomenon of arteries becoming less flexible and elastic, by a hardening and thickening of the artery walls, regardless of the underlying disease. In contract, atherosclerosis is a specific type of arteriosclerosis involving the buildup of cholesterol-containing plaque inside the artery walls. However, these terms are often used interchangeably.
Please see atherosclerosis
atherosclerosisThe term atheromatous describes the consistency of the plaque (Greek athero = porridge) which consists of cholesterol and in later stages, calcium deposits, immune cells and connective tissue. Only arteries and not veins are affected; atherosclerosis is the most common cause for arteriosclerosis, although the two terms are often used interchangeably. As plaque grows over time, blood flow in the narrowing artery becomes more restricted which can lead to several health problems:
Origin: Greek "hardening due to the formation of atheromatous plaque"
- When arteries leading to limbs are affected, circulation problems may develop in arms and legs called peripheral arterial disease
- When arteries to the heart are affected, coronary artery disease, chest pain (angina) or a heart attack can result
- When arteries supplying blood to the brain are affected, a transient ischemic attack or stroke could follow
- Atherosclerosis can also lead to a bulge in the wall of your artery called an aneurysm
Atorvastatin belongs to the the drug class of statins, effective against high cholesterol. With 2005 sales of US $12.2 billion under the brand name Lipitor? (manufactured by Pfizer), it is the highest selling drug worldwide.
Please see LDL
During bypass surgery, arteries or veins from elsewhere in the patient's body are transplanted to the heart to bypass atherosclerotic coronary arteries to improve the blood supply to the heart muscle.
Regarding the heart "cardio" and blood vessels "vascular"
CETPs or cholesteryl ester transfer proteins are liver enzymes that transfer cholesterol from HDL to LDL particles, turning "good" cholesterol into "bad" cholesterol. The primary effect of inhibiting CEPTs is a significantly increased serum HDL cholesterol level, with the lowering of bad LDL cholesterol a positive side effect.
CETP inhibitors are not yet available on the market, but several large pharmaceutical companies are working on this new drug class, including Pfizer (drug: torcetrapib), Merck (drug: anacetrapib) and Roche (drug code: R-1658).
This approach has been criticized since Pfizer's torcetrapib failed to lower heart problems in a recent clinical trial. As an unforeseen side effect, it actually raised blood pressure, thereby increasing heart problems and the overall risk of death.
Cholesterol is a fat-like substance that is vital to the human body. It is a component of every body cell, helping to maintain the stability and fluidity of cell membranes. Cholesterol is also used in the liver to produce cholic acid, a major constituent of the bile fluid necessary for the digestion of fat. Most of the body's cholesterol is made in the liver, but some is absorbed by food. Excessive blood cholesterol can lead to atherosclerosis.
Chylomicrons belong to the lipoprotein particles or tiny spheres that carry fat molecules throughout the blood stream. Chylomicrons are responsible for transporting fat and cholesterol absorbed by the gut through the bloodstream to various body tissues, mainly the liver.
coronary artery disease
Disorder of the coronary arteries that supply the heart muscle, usually narrowing or even complete blockage caused by atherosclerosis. This can lead to angina and eventually a heart attack. During bypass surgery, vessels that bypass the blocked arteries are implanted to improve blood flow to the heart.
The drug Crestor? contains the active ingredient rosuvastatin which can lower LDL cholesterol by approximately 40% when taken in a standard dose of 5-10 mg per day, and by up to 50% or more at higer doses. Rosuvastatin and atorvastatin (Lipitor?) are currently the most potent LDL cholesterol lowering drugs available. Crestor? is marketed by AstraZeneca under a license from Shionogi, Japan.
Please see arteries
A shuttling of cholesterol between the gut "entero" and liver "hepatic." Cholesterol is secreted with the bile fluid coming from the bile bladder in the liver and combines with cholesterol from food in the small intestine. The combined cholesterol is then partially secreted in stools, and partially reabsorbed only to end up back in the liver. The entero-hepatic cycle is believed to be a way the body eliminates excess cholesterol, although this mechanism is clearly not fine tuned, at least in individuals with high cholesterol.
Ezetimibe is the active agent of the drug Zetia? (marketed by Merck and Schering-Plough). It is not a statin, and works with a mechanism entirely different to those of statins by blocking the uptake of cholesterol in the gut. Ezetimibe may be taken by patients who can't tolerate statins.
Fibrates such as clofibrate are cholesterol and triglycerid-lowering drugs.
Death of tissue, usually due to insufficient oxygen supply. Typically, the narrowing or even complete blockage of the arteries of the legs with with pain walking or even death of foot or leg tissue is called gangrene, which is roughly comparable to "smoker's leg"
Please see HDL
HDL particles (high density lipoproteins) are a subclass of the lipoprotein particles or tiny spheres that carry fat molecules throughout the blood stream. HDL particles are able to collect cholesterol from body cells for reprocessing or elimination through the bile fluid) in the liver. By doing so, they provide a method to eliminate excess cholesterol that may otherwise accumulate in the body. The important thing is that they can also absorb cholesterol from artery walls which slows the buildup of plaque. These mechanisms counteract the harmful effects of high LDL cholesterol and may slow the progression of atherosclerosis. That's why HDL is also called "good" cholesterol. HDL cholesterol present in HDL particles is actually an indicator of how many vessel-cleaning HDL particles are present. HDL cholesterol is the only form of cholesterol you actually want to increase.
All the cholesterol present in HDL particles is called HDL cholesterol. Because HDL cholesterol is comparatively easy to measure, it serves as a proxy for the number of HDL particles which are difficult to count. Although HDL cholesterol contributes to total cholesterol, you want to increase the amount of this "good" cholesterol; having many HDL particles in your blood can delay the buildup of plaque in your arteries.
Sudden blockage of coronary arteries such as blood clots forming in atherosclerotic arteries can result in a heart attack, also known as a myocardial infarction. During a heart attack, a part of the heart muscle is no longer supplied with oxygen and nutrients. This part of the heart muscle may die if the blockage is not dissolved rapidly by medication and/or natural clot-dissolving processes in the body. Symptoms include a crushing chest pain that may radiate to the jaw or left arm, nausea, sweating and shortness of breath. Fainting is not very common.
HMG-CoA reductase is a key enzyme in the synthesis of cholesterol in the liver.
HMG-CoA reductase inhibitor
Drugs that impede HMG-CoA reductase, the key enzyme responsible for the body's synthesis of cholesterol in the liver. The body produces less cholesterol, which decreases the blood levels of cholesterol. Statins, the most important anti-cholesterol drugs currently available, are HMG-CoA reductase inhibitors.
Origin: Greek "Haima" = blood. High blood cholesterol or literally too much (hyper) cholesterol in the blood.
Greek "Haima" = blood. High blood lipids or literally too much (hyper) lipids in the blood. A somewhat imprecise term to indicate that any one or more of the blood lipids is too high.
Greek "Haima" = blood. High blood triglycerides or literally too much (hyper) triglycerides in the blood.
LDL particles (low density lipoproteins) are a subclass of the lipoprotein particles or tiny spheres that carry fat molecules throughout the blood stream. LDL particles, however, only carry cholesterol to the tissues throughout the body. The entire LDL particles are absorbed by body cells, which then use the cholesterol as building blocks for their cell membranes. Leftover LDL may return to the liver, where it is absorbed for storage and reprocessing. If too much LDL cholesterol is present in the blood, it tends to be deposited in the artery walls as soft, wax-like plaque. This is the first step towards atherosclerosis or hardening of the artery walls which can ultimately lead to heart disease.
All the cholesterol present in LDL particles is called LDL cholesterol. LDL cholesterol is called "bad" cholesterol, and at high blood levels can be deposited in artery walls, leading to atherosclerosis.
The drug Lescol? contains the active ingredient fluvastain and is marketed by Novartis. It can lower LDL cholesterol by approximately 30% when taken in a standard dose of 40mg per day.
Biological substances that are soluble in fat, but not water are called lipids. Among the lipids are triglycerides such as oil and fat, cholesterol, fatty acids and phospholipids (lecithin).
Lipitor? manufactured by Pfizer is a potent LDL cholesterol lowering drug, containing the active ingredient atorvastatin. It can lower LDL cholesterol by approximately 40% when taken in a standard dose of 10-20mg per day. Lipitor? is the world's best-selling drug, with 2006 revenues of nearly $13 billion, out of a worldwide total of $35 billion for statin drugs.
Being a fat-like substance, cholesterol is not water soluble. It can't flow freely through the blood, but quickly forms fatty droplets like grease drops in soup. The body's solution is to transport cholesterol, fat and oil (triglycerides) in specialized vehicles called lipoproteins. Lipoproteins, "lipoprotein complexes" or "lipoprotein particles" are tiny spheres that carry fat molecules throughout the blood stream. They consist of a water-soluble outer protein layer resting on a membrane of phospholipids which is another fat-like substance and an inner storage space holding cholesterol or cholesterol and triglycerides. Examples of lipoproteins include HDL or LDL particles and chylomicrons.
lipoprotein a, Lp(a)
Subclass of LDL particles containing the apolipoprotein 'a'. Apolipoprotein a counteracts the body's natural ability to dissolve smaller blood clots and increases the buildup op plaque in the arteries. High concentrations of Lp(a) in the blood are considered to be especially harmful for cardiovascular health.
The drug Lopid? contains the active ingredient gemfibrocil which belongs to the fibric acid drugs known as "fibrates." These drugs are used to lower serum triglycerides by as much as 60%, and may raise HDL cholesterol by as much as 20%. When combining fibrates with a statin drug, gemfibrocil seems to be the best choice, given that adverse drug interactions appear to be comparably low. Lopid? is marketed by Pfizer.
Lovastatin was the first statin approved by the FDA in 1987 under the brand name Mevacor? (manufactured by Merck).
The drug Mevacor? contains the active ingredient lovastatin which can lower LDL cholesterol by 30-40% when taken in standard doses of 20-40mg per day. Introduced in 1987, Lovastatin is the oldest statin on the market which means that its safety has been extensively studied. Mevacor? is marketed by Merck, which currenly plans to obtain approval for a prescription-free version of 20mg lovastatin per day.
Micelles are tiny spheres appearing in the gut after a meal. They are filled with cholesterol and fat, and are absorbed by cells lining the gut. Without micelles, cholesterol and fat could not be absorbed efficiently.
Please see heart attack
Substances that have vitamin B3 activity are collectively known as niacin. In fact, there are two substances that have Vitamin B3 activity: nicotinic acid and nicotinamide. 14-18mg of nicotinic acid per day is sufficient to satisfy the vitamin needs. However, when increasing the dose to 500-2000mg a day or up to 100-fold, it has drug properties and can raise HDL cholesterol by 15-30%, and may reduce serum triglycerides by 40-50%. A common side effect is facial flushing or reddening of the face and neck, sometimes accompanied by a burning or itching sensation. Nicotinamide, the other Vitamin B3, does not influence these lipids. Since niacin is the collective term describing both nicotinic acid and nicotinamide, it is not correct to state that niacin raises HDL or lowers triglycerides.
Niaspan? is an extended-release formula of nicotinic acid manufactured by Abbot Laboratories. The purpose of extending the release of the drug over a longer time period is mainly to lower flushing, the most common side effect of nicotinic acid.
Nicotinic acid (Vitamin B3 - also see "niacin") can raise HDL cholesterol and lower serum triglyceride levels when taken in large amounts (500-2000mg a day). Nicotinic acid is the active agent in Niaspan?.
peripheral artery disease
Peripheral artery occlusive disease (PAOD) are ones in which the large peripheral arteries that are distant from the body center (most commonly the legs) are blocked, mainly due to atherosclerosis. Symptoms of severe PAD include constant leg pain, foot or toe wounds that heal very slowly and gangrene.
Phytosterol is a plant-derived mixture of lipids that is chemically similar to cholesterol. It competes with cholesterol for the limited uptake capacity of cholesterol in the gut. Consequently, less cholesterol is absorbed. Phytosterols (plant sterols) can be used to lower blood cholesterol levels; a 2g daily dose may lower LDL cholesterol by 10-15%. One phytosterol called sitosterol was introduced by Eli Lilly in the 1950s under the brand name Cytellin. It had a very high safety record. However, with the development of statins, phytosterols became obsolete as prescription drugs. They can currently be found in dietary supplements or fortified products such as spreads and yogurts (eg in Take Control?/Promise? products by Lipton/Unilever).
Risk factors are habits or traits that increase the likelihood of certain diseases such as heart disease. Some important risk factors for heart disease include: high cholesterol, high blood pressure, smoking, physical inactivity and being overweight.
Simcor? is a new fixed-dose drug combination consisting of Niaspan? to raise HDL cholesterol and simvastatin to lower LDL cholesterol. It is currently develoed by Abbot Laboratories and may be introduced into the market by 2008.
One of the earlier statins which are powerful drugs against high cholesterol. Simvastatin is the statin used in the drug Zocor? (manufactured by Merck).
Sitosterol (beta-sitosterol) is the predomminant phytosterol in plants.
Statins are drugs that interfere with the biosynthesis of cholesterol in the liver, leading to lower blood levels of total cholesterol and LDL cholesterol. The "good" cholesterol HDL-C is usually not affected. Statins are quite powerful for reducing cholesterol levels -- a 30-50% reduction may be achieved with normal doses. Statins are also called HMG-CoA reductase inhibitors because they suppress the liver enzyme central to cholesterol synthesis, 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase). Examples of statins include atorvastatin (in the drug Lipitor? manufactured by Pfizer) and simvastatin (in the drug Zocor? manufactured by Merck).
Brain damage caused by an interruption of the blood and oxygen supply due to blockages by blood clots or the bursting of blood vessels. The severity of damage is dependent on the region of brain affected, the extent of the oxygen deficient area, and the time until the blood supply is re-established (transient ischemic attack).
Please see arteries
Forming of a thrombus or coagulation of blood in blood vessels, frequently causing obstructions at the site of formation and further down the bloodstream. This can lead to a heart attack or stroke.
The overall concentration of cholesterol measured in the blood. Nowadays, considered only to be a crude estimate of a person's heart disease risk. The allocation of total cholesterol to the different lipoproteins such as LDL and HDL are also measured, becuase they are more accurate in determining if medical intervention is required.
transient ischemic attack
A stroke with only transient loss of brain function due to insufficient blood flow in a region of the brain. Individuals normally experience a complete recovery within 24 hours.
Fat and oil are considered triglycerides, and are chemically comprised of glycerin and three "tri" fatty acids.
Veins are the blood vessels that return blood from the body to the heart, as opposed to arteries that deliver blood from the heart to the body). Blood pressure is always measured for the arteries, and is much lower (below 10 mmHg) in the veins.
The drug Vytorin? contains a combination of the active ingredients simvastatin and ezetimibe. As a mono-drug, simvastatin can lower LDL cholesterol by approximately 30-40% when taken in standard doses of 20-40mg per day. Ezetimibe as a mono-drug can lower LDL cholesterol by approximately 20%. Because the combination can lower cholesterol by approximately 50% or higher, Vytorin? is usually taken by patients at high coronary risk. Vytorin? is marketed by Merck and Schering-Plough under the tradename "Inegy."
VLDL particles (very low density lipoproteins) are lipoproteins that carry cholesterol and fat throughout the bloodstream. These particles are released from the liver into the bloodstream. They are similar to chylomicrons which originate from the gut because they both carry cholesterol and triglycerides which are gradually released in the bloodstream to be absorbed by body cells along the way. In the process of losing triglycerides, the VLDLs grow smaller and turn into IDLs (intermediate-density lipoproteins) and finally into LDLs which have lost all their triglycerides.
The drug Zetia? contains the active ingredient ezetimibe which can lower LDL cholesterol by approximately 20%. It is marketed by Schering-Plough and Merck.
The drug Zocor? contains the active ingredient simvastatin which can lower LDL cholesterol by approximately 30-40% when taken in standard doses of 20-40 mg per day. Zocor? was the world's fifth best-selling drug in terms of revenue in 2005. However, it lost its patent protection in 2006 and currently faces competition with cheaper generic drugs. Zocor? is marketed by Merck.