Gliptins

‘Gliptins’ is the nickname given to a group of medicines called dipeptidyl peptidase-4 inhibitors. The gliptins (active ingredient with brand name given in brackets) are:

• sitagliptin (Januvia)
• vildagliptin (Galvus)
• saxagliptin (Onglyza).
• linagliptin (Trajenta).

The gliptins are all relatively new medicines for diabetes. Linagliptin, saxagliptin, sitagliptin, and vildagliptin are all active ingredients in these medicines.

The gliptins are effective at lowering blood glucose, but they have not been used for long enough to know whether they also reduce the long-term complications of diabetes (such as heart disease and stroke). This will only become clear when they have been used by more people for longer periods of time.

Diabetes is a progressive condition. After a while, a single medicine will not be enough to control blood glucose levels. It could be months or years before this happens — but once it does, another kind of diabetes medicine will need to be added to metformin (and/or a sulfonylurea) to control blood sugar.

The gliptins are not taken on their own, but can be added to metformin, a sulfonylurea, or a glitazone.

Most commonly, people will start taking both metformin and a sulfonylurea when blood glucose cannot be controlled with a single medicine alone. However, some people can’t take this combination of medicines because they experience bad side effects, or they have another medical condition or another reason that means they can’t take metformin or a sulfonylurea (i.e. a contraindication). These people may have another kind of diabetes medicine added to their metformin (or sulfonylurea) instead.

The gliptins are one kind of diabetes medicine that can be used when this happens.

What do gliptins do?

Gliptins increase the amount of insulin in the blood when they are taken with metformin, a sulfonylurea, or a glitazone. They also reduce the amount of glucose produced by the liver.

What are the benefits of taking gliptins?

• Gliptins lower blood glucose levels at the recommended doses.
• All three gliptins appear to be equally effective.
• When taken together with metformin, gliptins don’t seem to increase the chances of hypoglycaemia or weight gain.
• They are an oral medicine and so are an alternative for people who cannot take a combination of metformin and a sulfonylurea.

Because gliptins are a new group of medicines, their long-term benefits are not fully known. For example it has not been shown that gliptins reduce the risk of developing the complications of diabetes (such as heart disease and stroke). This will only become clearer when they have been used by more people for longer periods of time, or when more research is done.

Who can take gliptins?

People with type 2 diabetes whose:

• blood glucose is inadequately controlled by metformin, a sulfonylurea or a glitazone alone
• levels of glycated haemoglobin (HbA1c) is higher than 53mmol/mol (>7%) who are not likely to respond to a single medicine alone may be prescribed saxagliptin (Onglyza) or linagliptin (Trajenta) together with metformin or a sulfonylurea.

You may not be able to take a gliptin if you have liver or kidney problems. Talk to your health professional as they may need to take this into account before deciding about prescribing a gliptin.

Note: Certain conditions apply before you can be prescribed sitagliptin, saxagliptin or vildagliptin on the PBS. At the time of publishing, these medicines can only be prescribed on the PBS for people whose diabetes is not well controlled with metformin or a sulfonylurea on its own. The medicine must be prescribed together with metformin or a sulfonylurea, and only for people who can’t take metformin and a sulfonylurea together (for example, because of side effects). See the Medicine Update for your medicine or www.pbs.gov.au for more information. 

What are the side effects of gliptins?

Gliptins can cause:

• hypoglycaemia and weight gain when used with a sulfonylurea, but not with metformin.
• dizziness, headaches and cold-like symptoms
• infections of the respiratory and urinary tract.

Allergic reactions to the gliptin occur very rarely. Seek medical attention if there is any swelling of the face, mouth, tongue or throat.

Saxagliptin (Onglyza) may also increase the chance of bone fractures.

Pancreatitis (inflammation of the pancreas that can result in severe, long-lasting abdominal pain) is rare, but has developed in a few people after starting linagliptin (Trajenta), sitagliptin (Januvia) and vildagliptin (Galvus). But it’s not known for sure if these medicines caused the pancreatitis. Talk to your health professional if you have any concerns.

Because gliptins are relatively new medicines, all of their side effects are not fully known. This will only become clear when they have been used by more people for longer periods of time.

To find out more, read our Medicine Update articles on saxagliptin, sitagliptin and vildagliptin.

Who can I ask about side effects?

Interactions

The gliptins are new medicines so not all of their potential interactions with other medicines are known.

Some medicines are known to affect blood glucose levels. Click on the following links to view tables that list some of these medicines:

• Medicines that decrease blood glucose
• Medicines that increase blood glucose.

Apart from these medicines, which can affect the way the gliptins control blood glucose:

• saxagliptin (Onglyza) may also interact with medicines that treat fungal infections (antifungals), such as ketoconazole.* You may need to take a lower dose of saxagliptin.
• linagliptin (Trajenta) can interact with the antibiotic rifampicin - rifampicin can decrease the amount of linagliptinin your blood and affect how well it works. You may need to take a different gliptin.

Read the Medicine Update issues about sitagliptin, vildagliptin and saxagliptin for more information.

*As there are often many different brands of one medicine, we have only listed the active ingredient of the medicine here. To find out more, read our information about active ingredients and brand names.