Review on using fibrates

• Introduction to Fibrates
• What are Fibrates
• Why are Lipid-Lowering drugs such as Fibrates used?
• Evidence regarding the use of Fibrates
• What does this mean?

Introduction to Fibrates

Fibrates are a form of ‘cholesterol lowering drug’ – that is, medications that are useful in lowering cholesterol and other lipids in the blood. Fibrates also increase the level of HDL or good cholesterol in the blood. They are often prescribed to people who are at high risk of cardiovascular problems such as atherosclerosis (hardening of arteries), heart attack and stroke. Though fibrates have been used for a number of years, there are still some doubts about whether they are more effective at reducing cardiovascular risk than other cholesterol-lowering drugs such as statins, and whether certain types of patients may be more suited to taking fibrates than others. A number of clinical trials have recently been conducted to try to answer these questions, and their findings are summarised below.

What are fibrates?

Fibrates are types of fat or lipid lowering medication. Lipids in the blood are mainly made up of cholesterol and triglycerides, and elevated levels of these have been associated with cardiovascular problems such as atherosclerosis (hardening of the arteries), heart attack and stroke. Fibrates are derivatives of fibric acid which are particularly suited to reducing triglyceride levels in the blood. Fibrates also have the effect of increasing HDL cholesterol (‘good cholesterol’). Common examples of fibrates include gemfibrozil, fenofibrate and clofibrate. See our page on fibrates for more information about how fibrates work, the different types of cholesterol, and why a fibrate might be prescribed.

Why are lipid-lowering drugs such as fibrates used?

Evidence from research studies has shown that a person’s risk of cardiovascular disease can be reduced by:

• lowering LDL cholesterol levels in the blood; and
• raising HDL cholesterol levels in the blood.

We also know that an increase in triglyceride levels is associated with increased risk of coronary heart disease, but it has not yet been shown that simply decreasing triglyceride levels can reduce a person’s risk. Because of this evidence, doctors may prescribe a lipid-lowering drug such as a fibrate to try to help change a patient’s blood lipid levels, and thus reduce their risk of cardiovascular disease. The treatment may be given before a patient develops clinical disease (known as ‘primary prevention’), or after they have already developed problems, such as following a heart attack (‘secondary prevention’) Drugs used for primary and secondary prevention of cardiovascular disease are given for many years, and so they have to fulfil a number of criteria to make their use worthwhile: they need to make you live longer or feel better, and they must be good enough at what they are designed to do to outweigh any possible negative effects of a taking medication for many years. It is therefore important that clinical trials are done to look at how effective they are, and that we look at the evidence these trials present carefully.

What is the evidence regarding the use of fibrates?

A number of trials have recently been undertaken worldwide to determine the effectiveness of fibrates in the prevention of cardiovascular disease. These include the Helsinki Heart Study, the Veterans Affairs High Density Lipoprotein Cholesterol Intervention Trial (VA-HIT), the Bezafibrate Infarct Prevention (BIP) trial, and the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial which focused on patients with diabetes and dyslipidaemia. Early results have indicated a general trend that fibrates can reduce cardiovascular events. Importantly, though, there has been no evidence that fibrates reduce mortality when compared to other lipid lowering drugs such as statins. Some studies have also suggested that fibrates may have some significant non-cardiac side effects that other drugs do not share. Some positive results have come out of the trials. Early evidence has suggested that fibrates may be particularly useful for patients with diabetes, due to their triglyceride-lowering effects. Fibrates may also be appropriate for use in patients at risk of acute pancreatitis due to high triglyceride levels.

What does this mean?

The evidence so far has shown us that although fibrates may be effective ‘on paper’ at lowering triglyceride levels, there are some factors that mean it is not an ideal first choice for medication in patients with risk factors for cardiovascular disease. This is mostly because there are other drugs that seem to be more effective at preventing cardiovascular effects, but also due to the associated side-effects of fibrates. In some cases however, a physician may choose to still use these medications either in conjunction with other medications or by themselves, according to the individual patient characteristics. You should discuss these issues fully with your doctor should you have any concerns. (Adapted from an article kindly contributed by Dr Jocelyne Benatar MBChB, Cardiovascular Research Unit, Greenlane Clinical Centre, Auckland, New Zealand.)

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(Adapted from an article kindly contributed by Dr Jocelyne Benatar MBChB, Cardiovascular Research Unit, Greenlane Clinical Centre, Auckland, New Zealand.)