9 Nov. 2006

High Cholesterol Deciding on Treatment

If you have high cholesterol, what does your doctor consider when selecting a treatment regimen? Learn more about the factors that affect cholesterol treatment decisions.

High Cholesterol: Deciding on Treatment

Choosing an appropriate treatment

What happens when your cholesterol levels are too high?

To reduce your risk of heart disease and stroke, your doctor will recommend a treatment that will help you get your cholesterol levels back to a healthy level. How is a treatment chosen?

The first step is to determine your risk of heart disease over the next 10 years. Your doctor can use a formula developed from a major heart disease study called the Framingham Study to calculate your risk of heart disease. To do this, the doctor will need to know your age, cholesterol levels, blood pressure, and whether you smoke.

Low to moderate risk

If your risk of heart disease in the next 10 years is low (less than 10%) to moderate (10-20%), your doctor will probably recommend that your try non-drug methods to lower your cholesterol first. Non-drug methods include:

* eating healthy

* quitting smoking

* moderating your alcohol intake

* maintaining an ideal body weight

* increasing physical activity

If these methods don't get your cholesterol down to a healthy level after 3 to 6 months, the doctor will consider adding a cholesterol-lowering medication. Medications are used in combination with non-drug methods, not by themselves.

High risk

If your risk of heart disease in the next 10 years is high (20% or more), your doctor will probably recommend starting a cholesterol-lowering medication right away, in combination with non-drug methods, to lower cholesterol.

If a medication is needed, your doctor will consider a number of factors in order to choose an appropriate medication for you. The doctor will take into account your medical conditions, other medications you are taking, your cholesterol levels, and any medication allergies you may have. You can also play an important part of the decision process - be sure you speak to your doctor about any concerns or questions you may have about medication treatment.

To learn more about different medications, read "Cholesterol medications" in this feature.

The contents of this site are for informational purposes only. Always seek the advice of your physician or other qualified healthcare provider regarding any questions you may have about a medical condition.

The ABCs of cholesterol levels

A cholesterol test measures the amount of cholesterol, or fats, in your blood. But it also measures more than that. Did you know that cholesterol comes in different "flavours," each with its own effects on the body? Here's the low-down on the different types of cholesterol and other fats that are measured in a cholesterol test:

* LDL (low-density lipoprotein): LDL is also known as the "bad" cholesterol. It is the cholesterol that builds up in your arteries, increasing your risk of heart disease.

* HDL (high-density lipoprotein): HDL is also known as the "good" cholesterol. It helps clean out LDL from your arteries, and can decrease your risk of heart disease.

* TG (triglycerides): Triglycerides are a type of fat that can increase the risk of blood clots and lower the amount of HDL in the blood. Unlike the other things measured in a cholesterol test, triglycerides are not a "flavour" of cholesterol. Rather, they are a different type of fat.

* VLDL (very low-density lipoprotein): VLDL is made into LDL in the body.

Other things measured in a cholesterol test include:

* TC (total cholesterol): This is the total amount of cholesterol in the blood, including LDL, HDL, and VLDL.

* TC:HDL-C ratio: This is called the "total cholesterol to HDL ratio." It is used to give doctors an idea of how much total cholesterol a person has relative to the HDL level. The ratio is calculated by dividing the total cholesterol by the HDL. It is a good measure of heart disease risk.

What should your numbers be? Read "Right on target" in this feature for more information.

Next:

Cholesterol medications

There are many different types of cholesterol-lowering medications, and they are all slightly different in terms of their effects on cholesterol, how they work, and their main side effects.

If you need a cholesterol-lowering medication, your doctor will make the choice based on your general health, which specific cholesterol "flavours" need to be adjusted (e.g., LDL, triglycerides, HDL), other medications you may be taking, and whether you have any medication allergies.

Statins

The "statin" group of medications includes atorvastatin (Lipitor®), fluvastatin (Lescol®), lovastatin (Mevacor® and others), pravastatin (Pravachol® and others), rosuvastatin (Crestor®), and simvastatin (Zocor® and others). They work by blocking cholesterol production in the liver. Statins have been shown to decrease the risk of heart disease and death in people with high cholesterol. The Canadian cholesterol guidelines, as published in the Canadian Medical Association Journal in 2003, recommend that everyone who is at a high risk of heart disease in the next 10 years be treated with a statin.

Here are the average effects of statins on cholesterol levels:

Type of cholesterol Effect Amount

TC (total cholesterol) Decrease Up to 40%

LDL (low density lipoprotein) Decrease 25-60%

HDL (high density lipoprotein) Increase 5-15%

TG (triglycerides) Decrease 10-45%

These effects depend on the dose and medication used. The effects of individual statins on cholesterol have been compared in clinical studies. One of the main studies compared atorvastatin, pravastatin, rosuvastatin, and simvastatin across a variety of doses. When researchers took an average across the different doses, they found that rosuvastatin lowered LDL by 8.2% more than atorvastatin, 26% more than pravastatin, and 12-18% more than simvastatin. Rosuvastatin also reduced triglycerides more than simvastatin or pravastatin.

One note of caution here: While higher doses may have a greater effect, they also increase the risk for side effects. One of the more serious side effects of statins is muscle breakdown, which can lead to kidney damage. Your doctor will order occasional blood tests to check for emerging problems. Stop taking the medication and contact your doctor if you notice changes in your urine colour or muscle pain, weakness, or cramps.

However, by and large, these medications are well tolerated, although some people may experience side effects such as mild stomach upset and headache.

Cholesterol absorption inhibitors

There is currently one cholesterol absorption inhibitor available in Canada: ezetimibe (Ezetrol®). It works by blocking cholesterol from being absorbed by the digestive system. It reduces absorption by about 54%. It can decrease LDL by about 18% and increase HDL by 3.5% when used alone. Ezetimibe may also be used in combination with other cholesterol-lowering medications such as the statins to help achieve target cholesterol levels. The main side effects of ezetimibe are headache, abdominal pain, and diarrhea.

Resins

This group of medications includes colestipol (Colestid®) and cholestyramine (Questran® and others). These medications work by decreasing the absorption of cholesterol and increasing the breakdown of LDL.

Here are the average effects of resins on cholesterol levels:

Type of cholesterol Effect Amount

LDL (low density lipoprotein) Decrease 15-30%

HDL (high density lipoprotein) Increase or decrease 3%

TG (triglycerides) Increase 3-10%

Colestipol is available as tablets, and both medications are available as powders or granules that are mixed in about 100 mL of fluid and swallowed. Since these resins may decrease how much of other medications are absorbed, there must be at least one to two hours between taking the resins and taking any other medications, including vitamins. The main side effects of resins are constipation, bloating, gas, and a feeling of fullness.

Fibrates

This group of medications works by blocking cholesterol production and increasing cholesterol breakdown. There are three fibrates available in Canada: bezafibrate (Bezalip®), fenofibrate (Lipidil Supra®), and gemfibrozil (Lopid® and others). These medications were among the first medications discovered to lower cholesterol.

The average effects of fibrates on cholesterol levels are:

Type of cholesterol Effect Amount

LDL (low density lipoprotein) Increase or decrease 10%

HDL (high density lipoprotein) Increase 10-30%

TG (triglycerides) Decrease 20-50%

The main side effects of fibrates are nausea, abdominal pain, gas, and muscle aches. People taking fibrates will usually have regular liver and kidney function tests. There is some concern that taking these medications along with a statin medication may increase the risk of muscle problems.

Niacin

Niacin, or vitamin B3, works by decreasing the production of LDL and TG and blocking the breakdown of HDL. Its effects on cholesterol levels are:

Type of cholesterol Effect Amount

LDL (low density lipoprotein) Decrease 15-30%

HDL (high density lipoprotein) Increase 20-35%

TG (triglycerides) Decrease 30-60%

The main side effects of niacin include flushing, itching, dry skin, and stomach irritation. Some people find that flushing is less pronounced with extended-release niacin, and most people who experience flushing find that the side effect diminishes with continued therapy. High-dose niacin can cause liver toxicity, so people taking this vitamin to lower cholesterol should inform their physician.

Right on target

Once a treatment is chosen, how do you know if it's working?

On the basis of your heart disease risk, your doctor will choose cholesterol "target" levels for you. Reaching these levels by taking a cholesterol medication every day will reduce your risk of heart disease and stroke to an acceptable level. After you start a new cholesterol medication, your doctor will measure your cholesterol levels regularly. The goal is to get your cholesterol levels to the target values your doctor has set for you. Once your target is achieved, you will need to continue to take medication to maintain that level. If you stop your medication, levels will rise again.

How are target levels chosen?

Targets are based on your risk of heart disease and stroke. Your doctor will calculate this risk using a formula developed from a major heart disease study called the Framingham Study. The formula uses your age, cholesterol levels, blood pressure, and whether you are a smoker to determine your risk level.

What are the target levels?

The Canadian cholesterol guidelines, as published in the Canadian Medical Association Journal in 2003, recommend the following target levels for cholesterol:

Risk group 10-year risk of heart disease Target LDL* (mmol/L) Total cholesterol:HDL ratio

Low 10% or less less than 4.5 AND less than 6.0

Moderate 11-19% less than 3.5 AND less than 5.0

High 20% or greater less than 2.5 AND less than 4.0

*To learn more about LDL, HDL, and total cholesterol, see "The ABCs of cholesterol levels" in this feature. In Canada, cholesterol levels are measured in mmol/L. To convert to US values, multiply by 38.7.

The guidelines have changed over the years, and now recommend lower cholesterol targets than before. Some people can reach their target levels just by using non-drug methods, others can get to target with one medication, and others require a combination of drugs to reach their cholesterol targets.

The guidelines do not include a target level for triglycerides, but levels of 10.0 mmol/L or more should be treated because they increase the risk of pancreatitis (inflammation of the pancreas). An ideal level for triglycerides is 1.7 mmol/L or less.

Why are target levels important?

It's important to know your cholesterol target levels and whether you are reaching them. This is because reaching your targets will help reduce your risk of heart disease and stroke. If you're not sure whether you are meeting your target levels, check with your doctor.