Exenatide (Byetta) for type 2 diabetes

Published in Medicine Update

Date published: About this date

Health and medicines information in this article may have changed since the date published. This information does not replace advice from a health professional.

This Medicine Update is for people who are using, or thinking about using, exenatide.

Summary

Exenatide is a new injectable medicine that reduces blood glucose levels. It is just one of several options for people at this stage of their treatment. Insulin, and medicines called glitazones and gliptins are others.

Exenatide can be used by people with type 2 diabetes whose blood glucose cannot be controlled effectively with certain other medicines. If you are prescribed exenatide, you will take it in addition to your existing diabetes medicines.

Like all new medicines, the long-term benefits and all of the side effects of exenatide are not fully known.

Contents


What exenatide is

The active ingredient of this medicine is exenatide (pronounced eks-EN-A-tide). It is also known by the brand name Byetta.

Exenatide is an injectable medicine for type 2 diabetes. It is not the same as insulin. Nor is it a type of insulin.


What exenatide is for

Exenatide treats type 2 diabetes.

People with type 2 diabetes have too much glucose (sugar) in their blood because their body does not produce enough insulin or their insulin has become less effective (called insulin resistance).

Having high blood glucose levels increases your risk of developing the long-term complications of diabetes.

These complications are serious. People with diabetes may develop heart disease, kidney disease, eye disease, pain or loss of feeling and poor circulation in the feet, and problems with sexual function.

Exenatide treats type 2 diabetes by controlling blood glucose levels.


Who can use exenatide

Exenatide is available on the Pharmaceutical Benefits Scheme (PBS) for people with type 2 diabetes, but there are some restrictions on its use.

In general terms, you can get exenatide through the PBS if your HbA1c is over 7%:

  • despite taking metformin (e.g. Diabex, Diaformin) and a sulfonylurea (e.g. Amaryl, Daonil, Diamicron, Minidiab) at the same time, or
  • despite taking metformin or a sulfonylurea (and you are unable to take a combination of these medicines).

Please note — exenatide is not taken on its own. You will need to continue taking your metformin and/or sulfonylurea when you start using exenatide.

HbA1c is a measure of your average blood glucose levels over the previous 10–12 weeks.

You cannot get exenatide through the PBS if you are already using insulin, or taking other medicines for your diabetes called glitazones or gliptins.

Speak to your doctor if you have kidney problems. You may still be able to use exenatide, but your doctor will have to take this into account before prescribing.


How to use exenatide

Exenatide is an injectable medicine supplied as a pre-filled disposable pen. You inject it under the skin twice a day.

You should inject exenatide:

  • within the hour before your breakfast, and
  • within the hour before your evening meal.

Do not use exenatide after a meal.

The usual dose is one 10 microgram injection twice a day. You will start with a smaller dose of one 5 microgram injection twice a day for the first few weeks, and then go up to the usual dose. This should help reduce the side effects described in Important side effects of exenatide to consider.

Your doctor will show you how to inject exenatide using the pre-filled disposable pen.


When you can use exenatide

Exenatide is not a medicine to use when you first develop type 2 diabetes. It would be a second or third medicine, added to your existing medicines.

There are alternatives to exenatide at this stage, such as insulin injections. Insulin can be used when metformin and sulfonylureas no longer control blood glucose.


What does exenatide do?

Exenatide reduces glucose levels in the blood. It does this by:

  • increasing the amount of insulin in the blood
  • reducing the amount of glucose produced by the liver
  • helping the stomach to empty more slowly so that glucose is absorbed more slowly.

It is not yet known if exenatide reduces the long-term complications of diabetes (see Other medicines available for type 2 diabetes).


Important side effects of exenatide to consider

The most common side effects with exenatide are those affecting the stomach. Some people feel nauseous when they start using exenatide. A few might need to stop the medicine because the nausea is so bad — if you find exenatide makes you too ill, you should discuss stopping it with your doctor. But for most people, the nausea settles down within a week or two and they can continue using exenatide.

Ask your health professional about the possible side effects of this medicine before you take it. Always tell them about any changes to your condition if you're taking a new medicine.

To report possible side effects call the NPS Adverse Medicine Events (AME) Line on 1300 134 237 from anywhere in Australia (Monday–Friday, 9am–5pm AEST).

People with questions about their medicines or seeking general information about side effects can call the NPS Medicines Line on 1300 633 424 (Monday–Friday, 9am–5pm AEST).

Other possible stomach side effects are loss of appetite, vomiting, diarrhoea and heartburn.

Headaches, dizziness and feeling jittery are also fairly common. So is soreness and redness or swelling at the injection site.

People using exenatide can have hypoglycaemic episodes (when blood glucose drops below normal levels), particularly if they are also taking a sulfonylurea (e.g. Amaryl, Daonil, Diamicron or Minidiab).

Rarely, some people developed pancreatitis or kidney problems while taking exenatide. But it's not known for sure if exenatide caused the pancreatitis or kidney problems. Some of those who developed kidney problems already had kidney disease, or were at risk of kidney problems.

For a more complete list of possible side effects for Byetta (exenatide), see the consumer medicine information (CMI) leaflet available on our Medicines Finder page.


What else you should know about exenatide

In some clinical trials, people using exenatide lost a small amount of weight. The average weight loss was 1–2 kg over a few months to a year. It is not known whether or not this weight loss would be maintained if the medicine was used for a long time. Note, exenatide is not a weight-loss medicine, and should not be used to help lose weight.

Some other medicines for diabetes cause a small weight gain (see Other medicines available for type 2 diabetes).

Use a medicines list to help keep track of the medicines you are taking. Take it with you each time you visit a health professional, or if you go into hospital.

Get an NPS Medicines List or download the free iPhone app.

Exenatide affects the absorption of other medicines. This means you might have to change the timing or dose of your other medicines. Talk to your doctor or pharmacist about when you should take your other medicines. And tell them about all the medicines you take, including any you get from a pharmacy, supermarket or health food store.

Storing exenatide

You will need to store exenatide in a refrigerator. Do not freeze it.


Other medicines available for type 2 diabetes

Most people start taking medicines when lifestyle changes, diet and exercise are not sufficient to manage their diabetes.

Your medicine options will depend on your blood glucose control, your response (including side effects), your age and health, and other medicines that you are taking.

The medicines you take for your diabetes may change over time. For example, you might only need a single tablet — like metformin or a sulfonylurea — to control your blood glucose initially. But diabetes tends to get worse as you get older, and at some point your doctor may recommend that you take more than one type of tablet, or that you use insulin, or a combination of tablets and insulin. Each medicine will work in a different way to control your blood glucose level.

The other types of medicine you might take are:

  • metformin
  • sulfonylureas
  • glitazones
  • gliptins
  • insulin
  • acarbose and repaglinide.

Metformin

Metformin (e.g. Diabex, Diaformin) is the first tablet most people take for type 2 diabetes. It makes your own insulin more effective and reduces the amount of glucose produced by your liver.

Metformin may cause nausea, loss of appetite and diarrhoea.

Sulfonylureas

Sulfonylureas are often added to metformin. They may also be used as the first tablet by people who cannot take metformin. Sulfonylureas increase your body's production of insulin.

The sulfonylureas include glibenclamide (e.g. Daonil), gliclazide (e.g. Diamicron), glimepiride (e.g. Amaryl, Dimirel) and glipizide (e.g. Minidiab).

Many people taking sulfonylureas gain weight and may have hypoglycaemic episodes. Allergic reactions may occur.

Glitazones

Pioglitazone (Actos) and rosiglitazone (Avandia) are relatively new medicines for type 2 diabetes. Like sitagliptin and vildagliptin (see below), pioglitazone and rosiglitazone can be taken with metformin or a sulfonylurea. Glitazones make your own insulin more effective.

Glitazones can cause fluid retention and weight gain, and increase the risk of some bone fractures in women.

Glitazones are not suitable for people with heart failure. Rosiglitazone should not be used by people with heart disease.

Gliptins

Sitagliptin and vildagliptin reduce the amount of glucose in the blood when taken with metformin or a sulfonylurea. They also reduce the amount of glucose produced by the liver.

Some people have headaches or develop cold-like symptoms when taking a gliptin.

For more information see the NPS Medicine Update on sitagliptin and the Medicine Update on vildagliptin.

Insulin

If you can no longer make enough of your own insulin, tablets such as metformin and sulfonylureas will not work properly. At this point your doctor might suggest that you start using insulin to control your blood glucose level.

Insulin can be used on its own or with some other medicines for type 2 diabetes.

Insulin is injected — usually once, twice or three times a day. While many people worry about injecting insulin, most find the injections are not painful.

The main side effects of insulin are weight gain and hypoglycaemia. Allergic reactions are possible and some people get skin reactions at the site of injections.

See the section on insulin in the NPS knowledge hub on type 2 diabetes.

Acarbose and repaglinide

Acarbose (Glucobay) and repaglinide (Novonorm) are used by a small number of people for whom other medicines are unsuitable.


How to decide between exenatide and other medicines

There are two main reasons to treat your diabetes:

  • to keep your blood glucose levels down
  • to reduce your risk of developing the complications of diabetes.

A medicine that suits one person may not suit another. You may wish to avoid certain side effects or, if the medicine is working well, you may be willing to put up with the possible side effects.

Like all medicines used for type 2 diabetes, exenatide reduces the level of glucose in the blood.

But it is not known if it can reduce your risk of developing the complications of diabetes. This will only become clear when exenatide has been used by more people for longer periods of time.

Insulin, metformin and sulfonylureas have been shown to reduce the complications of diabetes. This is a very important benefit of these medicines.


What does exenatide cost?

Most medicines prescribed by your doctor are covered by the Pharmaceutical Benefits Scheme (PBS). This means that the Australian Government pays most of the cost of your medicine. For more information see www.pbs.gov.au.

Cost to the Government

The full cost of exenatide to the Australian Government is:

  • $176.39 for a 5 microgram or 10 microgram exenatide injection pen.

Cost to the individual

If you get exenatide through the PBS you will pay only part of the cost, called the co-payment. At the time of publication, the co-payment for people who are entitled to get exenatide through the PBS was:

  • $33.30 for people without a concession card
  • $5.40 for concession card holders.

Each prescription lasts 30 days, and you can get up to 5 repeats.

If you are not eligible to get exenatide through the PBS, you will need to pay the full price for a prescription.


Other ways to help type 2 diabetes

A healthy, balanced diet is important for all people with diabetes. A dietitian, diabetes educator or doctor can help you with this.

Physical activity

Regular physical activity is important for managing diabetes. Many people find that their diabetes is easier to manage with regular physical activity (e.g. 30 minutes of physical activity on five or more days per week). Resistance training (e.g. using light weights) is recommended, as is aerobic exercise (e.g. walking or cycling). A diabetes educator, exercise physiologist or doctor can help you with this.

Diet

If you have just been diagnosed with type 2 diabetes, your doctor will usually recommend that you eat a healthy, balanced diet and exercise regularly for three months to see if this controls your diabetes without the need for medication (unless the symptoms of diabetes are severe).

Even when using medicines, you should continue to follow a healthy, balanced diet and carry out regular exercise. This can help you to maintain a healthy weight. It may also improve your blood glucose control, reduce your need for medicines and help to prevent some of the long-term complications of diabetes.

Testing your glucose

Testing your own blood glucose levels regularly can help you to manage your diabetes. Speak to your diabetes educator or doctor.

Smoking

If you smoke, you should make every effort to quit. The combination of smoking and diabetes greatly increases the risk of heart disease and other complications of diabetes. Quitting smoking will also have a positive impact on your health and substantially reduce your risk of other illnesses. For more information, contact the Quitline on 13 QUIT (13 7848) or get an online quitting coach from www.quitcoach.org.au.

Alcohol

If you drink alcohol, then a low-to-moderate intake is best. You should discuss this with your health professional. Alcohol can interact with some diabetes medicines, and make hypoglycaemia more likely.

Blood pressure

If you have diabetes and high blood pressure, it's important that you work with your doctor to keep your blood pressure under control. Studies have shown that good blood pressure control can prevent some of the long-term complications of diabetes.

For more information, contact Diabetes Australia on 1300 136 588 or at www.diabetesaustralia.com.au.

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Where to find more information

You can find more information in the consumer medicine information (CMI). This will tell you:

  • who should not use the medicine
  • which other medicines should be avoided
  • how to take the medicine
  • most of the possible side effects
  • the ingredients.

You can get the CMI leaflet for Byetta from:

Information over the phone

NPS works with healthdirect Australia to provide the Medicines Line phone service for consumers.

To get more information about any medicine call 1300 MEDICINE (1300 633 424). This service is available from anywhere in Australia, Monday to Friday, 9am to 5pm AEST excluding NSW public holidays.

To report a side effect

Call the NPS Adverse Medicine Events (AME) Line on 1300 134 237, Monday to Friday, 9am to 5pm AEST excluding public holidays.

The AME Line is a service where you can report possible side effects of your medicine and contribute to national medicine safety efforts. Information on medicine-related side effects is passed on to the Therapeutic Goods Administration (TGA) for assessment, but your personal details will remain confidential and your privacy maintained.

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