Why you have been prescribed lipid-lowering medication

If you have so-called 'high cholesterol' your doctor will usually have given you dietary guidelines and modifications to follow for at least six weeks. If adjusting your diet does not improve your cholesterol levels, your doctor may prescribe medication to lower your level of cholesterol or fats in your body. Doctors often call these medications 'lipid-lowering drugs' (cholesterol or other types of fat are known as lipids).

Do we need cholesterol?

Your body needs some cholesterol and other lipids to carry out its essential functions; however, when you have too much of the bad kind of lipids they can cause atherosclerosis.

What is atherosclerosis?

Atherosclerosis is when lipids build up on the inside wall of your arteries causing narrowing of the blood vessel, which slows the blood flow. Sometimes clots can form which block the artery completely. This has severe consequences when it happens in the coronary arteries.

The coronary arteries supply the heart muscle with blood, bringing it oxygen so it can pump. If they become blocked, part of the heart muscle may die, causing a heart attack. Taking lipid-lowering medications can slow the progression of atherosclerosis.

Different types of lipids

When your doctor sends you for a blood test to measure your cholesterol, the test will usually measure your total cholesterol, which is made up of low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and also your triglycerides.

LDL cholesterol is the so-called 'bad' cholesterol. The level of LDL in a person's blood is linked to atherosclerosis and can predict their risk of having coronary heart disease. The New Zealand Heart Foundation recommends LDL to be below 2.0 mmol/L for the majority of patients; however, for those who are already at a higher risk of coronary heart disease an LDL lower than this may be recommended. To assess your own cardiovascular disease risk click here.

HDL is often called the 'good' cholesterol as it can actually help carry cholesterol away from the arteries to the liver, where it is processed and excreted from the body. A high proportion of HDL in your total cholesterol level may be beneficial in reducing the risk of coronary heart disease.

Although LDL is the main culprit in terms of risk of atherosclerosis, high levels of triglycerides in the blood are also considered to be important predictors of future coronary problems, and very high levels of triglycerides may cause inflammation of the pancreas (pancreatitis).

Keeping your cholesterol within healthy limits

The New Zealand Guidelines Group publishes guidelines on healthy blood levels of cholesterol and triglycerides and your doctor will probably use these to decide whether to treat you.

In addition to lifestyle and diet adjustments, which may help keep your lipid levels in the healthy range, your doctor may prescribe medication to help keep your lipid levels under control.

Medications used for lipid lowering

Your doctor will make a decision on the type of medication you should take partly based on the results of your blood test. This tells your doctor which type of lipids you have too much of and he or she will treat you accordingly.

Statins 

Statins is the name for a particular class of medications. Statins include atorvastatin, simvastatin and pravastatin. Doctors sometimes also refer to this group of medications as the HMG CoA reductase inhibitors.

Statins work by interfering with an enzyme the body uses to make cholesterol so that it can't make as much. They also increase the amount of cholesterol the liver takes up and removes from the blood.

The net result is that they can reduce the amount of LDL cholesterol by about 20% to about 55%, depending on the dose and the type of statin being taken. They can also produce a small increase (5% to 15%) in 'good' cholesterol, that is, HDL cholesterol, depending on the dose and type of statin.

Your doctor will advise you how to take your statin medication. The most common side effects of the statin drugs are stomach upset and headache, and in a small number of patients muscle aches and pains.

If you develop pain in your muscles or any tenderness or weakness, please make an appointment to see your doctor as soon as possible. Your doctor may also want you to have some blood tests when you start treatment with statins so that your progress can be monitored.

Cholesterol absorption inhibitors

A new class of cholesterol-lowering agents is known by doctors as cholesterol absorption inhibitors (eg, ezetimibe). Ezetimibe reduces total cholesterol, LDL or 'bad' cholesterol and triglycerides, and increases HDL ('good') cholesterol.

Ezetimibe lowers cholesterol by reducing its absorption from the intestine into the bloodstream. Your doctor may prescribe ezetimibe if you are already using a statin and your cholesterol level is still raised, because taking both of these medicines together can be more effective in lowering LDL cholesterol than taking a statin alone. Ezetimibe may also be prescribed by your doctor if statin medication is not suitable for you.

Ezetimibe is also available combined with simvastatin in one tablet.

Ezetimibe can be taken with or without food, at any time of the day (but should be taken at about the same time every day). If you are pregnant, breastfeeding or have any liver problems, ezetimibe may not be an appropriate medication for you. If you are taking ezetimibe and a statin and you develop muscle aches, you should see your doctor as soon as possible.

Bile-acid-binding resins

Cholestyramine and colestipol are medications known by doctors as bile-acid-binding resins. They are called this because they bind to bile acids in the intestine, preventing them from being reabsorbed into the body and so releasing the bile acids in the faeces. To make more bile acids, the body needs cholesterol. This results in a higher demand for cholesterol by the body, which plays a part in reducing the blood level of cholesterol.

Cholestyramine comes in sachets of powder, which need to be mixed with water, juice or other fluid. If you find it too gritty you can mix the dose and stand it in the refrigerator for four hours or even overnight. Colestipol also comes as powder in sachets and needs to be mixed with water. It can be taken with or without food. Sometimes these medications cause constipation.

Fibrates

Fibrates (eg, bezafibrate) are a group of lipid-lowering medications that are often prescribed by a doctor if you have predominantly high blood triglycerides, as opposed to other lipids, or when other lipid-lowering drugs do not agree with you.

Bezafibrate lowers elevated blood triglyceride levels by about 20% to 50% and sometimes lowers 'bad' LDL cholesterol by a small amount. Bezafibrate raises 'good' HDL cholesterol levels by about 10% to 15%.

Bezafibrate reduces blood triglycerides by increasing the activity of enzymes that clear triglycerides from the blood, and it also reduces the production of cholesterol by the liver.

Bezafibrate should be taken as directed by your doctor, with a glass of water and with food.

Side effects can occur in some patients, the most common being nausea, bloating or gastrointestinal upset. If you experience any skin rash, itching or other effects you should tell your doctor as soon as you can.

Nicotinic acid

It is not entirely clear how nicotinic acid works to lower lipid levels. However, nicotinic acid can lower LDL cholesterol (the 'bad' cholesterol) and triglycerides and also increases the 'good' cholesterol (HDL cholesterol). Nicotinic acid is often used where the lipid that is predominantly elevated is triglyceride.

Nicotinic acid tablets are usually taken three times a day. They may cause flushing of your face and neck. This often goes away after two to six weeks, but sometimes comes back if you have missed doses. Please see your doctor if this happens because your doctor may be able to give you something to stop the flushing.

Your doctor may also want you to have some blood tests when you start treatment with nicotinic acid in order to monitor your progress.

If you have recently had a heart attack, nicotinic acid will not be suitable for you.

Fish oil

Fish oil is commonly available. Fish oil is used for lowering triglycerides and does not seem to have many side effects. Sometimes your doctor may suggest fish oil in combination with a statin medication or one of the other lipid-lowering medications mentioned here. Eating fish in moderate quantities may achieve the same result as taking fish oil, so your doctor may recommend that you eat fish at least twice a week.

Plant sterols

Plant sterol margarines and spreads are another option for lowering cholesterol. A daily intake of 1 to 1.5 tablespoons is the recommended amount. Eating more than this has no additional benefit. Because these spreads are relatively new, doctors are still collecting data on their long-term safety.

People using the spreads should make sure that they eat orange and yellow vegetables and fruits each day to minimise any decrease in carotenoids. Carotenoids are plant pigments, such as beta-carotene (found in carrots), that seem to have anticancer, antioxidant and heart protective effects.

Consumer information on prescription medicines

For more information on prescription medications, you can search MedSafe's Consumer Medicines Information (CMI).

Original material provided by myDr. Reviewed and edited by everybody in February 2011.