Sitagliptin (Januvia) for type 2 diabetes Medicine Update August 2010: Sitagliptin (Januvia) for type 2 diabetes

1. What sitagliptin is

The active ingredient is the chemical in the medicine that makes the medicine work.

Many medicines are known by their brand names as well as by the name of the active ingredient. Some medicines are available under several different brand names.

The active ingredient of this medicine is sitagliptin (pronounced SIT-a-GLIP-tin). It is also known by the brand name Januvia.

Sitagliptin is a medicine for type 2 diabetes.

Sitagliptin is also one of the active ingredients in a combination medicine for type 2 diabetes called Janumet. The other active ingredient is metformin. Janumet is not discussed in this leaflet.

2. What sitagliptin is for

Sitagliptin 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. 

Sitagliptin treats type 2 diabetes by controlling blood glucose levels.

3. Who can take sitagliptin

Talk with your doctor about all the treatment options for type 2 diabetes.

Sitagliptin 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 sitagliptin through the PBS if:

• you are already taking metformin (e.g. Diabex, Diaformin) or a sulfonylurea (e.g. Amaryl, Daonil, Diamicron, Minidiab), and
• your HbA1c (a measurement that reflects your average blood glucose levels over the last 10–12 weeks) is over 7%, and
• you cannot use a combination of metformin and a sulfonylurea, or the combination causes you intolerable side effects.

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

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

4. How to take sitagliptin

Take one sitagliptin tablet at the same time each day.

You can take sitagliptin tablets with or without food. Swallow the tablets whole with a glass of water.

5. What does sitagliptin do?

Sitagliptin 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.

It is not yet known if sitagliptin reduces the long-term complications of diabetes (see section 9).

6. Important side effects to consider

For a list of possible side effects, see the consumer medicine information leaflet for sitagliptin.

Ask your doctor about the possible side effects of this medicine before you use it.

Always tell your doctor about any changes to your condition if you are taking a new medicine.

You can also discuss side effects with a pharmacist, by calling the Adverse Medicine Events (AME) Line on 1300 134 237 (Mon–Fri, 9am–5pm).

A clinical trial is a research study conducted with patients, which compares one treatment with one or more other treatments, or with no other treatment, to assess its effectiveness and safety.

The most common side effects of sitagliptin are headache and cold-like symptoms.

Some rare but serious side effects can occur with sitagliptin, such as:

• allergic reactions
• pancreatitis (inflammation of the pancreas that can result in severe, long-lasting abdominal pain).

Allergic reactions are rare, but you should seek medical attention if you have any swelling of the face, mouth, tongue or throat.

Pancreatitis has developed in a few people after starting sitagliptin. But it’s not known for sure if sitagliptin caused the pancreatitis.

Sitagliptin has been tested in clinical trials, but it is still quite a new medicine so the full range of side effects is not yet known. You should be aware of this and talk to your doctor if you have any concerns.

7. What else you should know about sitagliptin

Some other medicines can interact with sitagliptin.

You should tell your doctor about all the medicines you take, including any you get from a pharmacy, supermarket or health food store.

8. 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 take 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
• exenatide
• insulin
• acarbose and repaglinide.

Vildagliptin (Galvus) is another medicine you may be asked to consider. It belongs to the same group of medicines as sitagliptin. You can read more about vildagliptin here.

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 (when blood glucose drops below normal levels). Allergic reactions may occur.

Glitazones

Pioglitazone (Actos) and rosiglitazone (Avandia) are relatively new medicines for type 2 diabetes. Like sitagliptin, 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.

Exenatide

Exenatide (Byetta) is a new injectable medicine, but it is not insulin. It is used in addition to tablets to help reduce blood glucose levels.

Some people feel nauseous when they start using exenatide. People using exenatide can have hypoglycaemic episodes, particularly if they are also taking a sulfonylurea.

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. Sitagliptin is not usually used with insulin.

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.

For more information about starting insulin, see this information leaflet.

Acarbose and repaglinide

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

9. How to decide between sitagliptin and other medicines

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.

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.

Like all medicines used for type 2 diabetes, sitagliptin 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 sitagliptin 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.

Weight gain and hypoglycaemia

Most medicines for type 2 diabetes — except metformin— can sometimes cause hypoglycaemia. Hypoglycaemia is more likely with insulin than with tablets, and is more likely with sulfonylureas than with other tablets.

Sitagliptin does not appear to increase the risk of hypoglycaemia when taken with metformin. Nor does it cause weight gain. However, hypoglycaemia and weight gain may still occur if sitagliptin is used with a sulfonylurea.

10. What does sitagliptin cost?

Most medicines prescribed by your doctor are covered by the PBS. This means that the Australian Government pays part of the cost of your medicine.

You will need to pay the full price if the medicine is not available on the PBS, or is not available on the PBS for your specific condition.

For more information see www.pbs.gov.au.

Cost to the Government

The full cost of sitagliptin to the Australian Government is:

• $91.19 for 100 mg, 50 mg or 25 mg  sitagliptin tablets (pack size 28 tablets).

Each prescription lasts 28 days, and you can get up to 5 repeats.

Cost to the individual

If you get sitagliptin through the Pharmaceutical Benefits Scheme (PBS), the Australian Government pays most of the cost and you will pay only a part, called the co-payment.

At the time of publication, the co-payment for people who are entitled to get sitagliptin through the PBS was:

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

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