Diabetes Medications and New Drugs

Sitagliptin (Januvia)


Type 2 diabetes is usually associated with progressive exhaustion or failure of beta cells of the pancreas which produce insulin. Most patients require increasing doses of oral hypoglycaemic agents eventually needing transfer to insulin treatment. The main oral drugs used to treat type 2 diabetes are Metformin, sulphonylureas and the Glitazones. Now the first of a new class of oral blood sugar lowering agents ‘the Gliptins’ or oral DPP-IV inhibitors has been launched in the UK.

What is Januvia?

Januvia or Sitagliptin is the first of a new class of drugs for the treatment of Type 2 diabetes. Januvia is a ‘trade name’ whereas Sitagliptin is it’s generic name. This group of drugs will be known as DPP-IV (dipeptyl peptidase-IV) inhibitors. Januvia is produced by a pharmaceutical company called Merck Sharp & Dohme Ltd (address given below).

How do these new drugs work?

Sitagliptin reduces blood glucose concentrations by enhancing the effects of ‘incretins’. Incretins are hormones (chemicals) which are produced by the gut (bowel) in response to food. These drugs are therefore also known as ‘incretin enhancers’.

More about gut hormones

When you have a meal various hormones are released by cells in the gut (bowel) wall. These hormones help stimulate the release of insulin by the pancreas. This action is known as the ‘incretin effect’. It has been shown that people with type 2 diabetes have an impaired incretin effect.

The role of DPP-IV

Incretin hormones have a very short life-span in circulation, as they are rapidly destroyed by DPP-IV. DPP-IV is a naturally occuring enzyme (chemical) which is involved in breaking down incretin hormones. By opposing the action of DPP-IV, Januvia helps to prolong the incretin effect. This helps reduce blood glucose levels.

What are the potential benefits of Januvia?

  • Sustained lowering of blood glucose
  • Well tolerated – low rates of adverse effects in clinical trials
  • Not associated with weight gain
  •  Oral administration
  • Once daily dose 

As yet there are no long term studies of Januvia in people with Type 2 diabetes. We do not know therefore, if it confers any benefit on life expectancy.

What are the side effects?

Side effects resulting from the use of Januvia are uncommon. Nausea may occur. Flatulence has been reported. When combined with glitazones swelling of the feet may be seen. As with some other oral blood glucose lowering drugs, hypoglycaemia may occur.

Who should not take Januvia?

You should not take Januvia if you have

  • type 1 diabetes
  • previously had diabetic ketoacidosis
  • kidney problems

Are there other benefits beyond blood glucose lowering?

It is known that people with type 2 diabetes have progressive loss of beta cell function. It is possible that Sitagliptin may help preserve pancreatic beta-cell function.

When is it likely to be used?

It is likely to be used in people whose diabetes is not controlled with Metformin and other oral hypoglycaemic agents.

How is it administered?

Sitagliptin is taken orally and is administered once daily. It is available as a film-coated tablet in a single strength of 100mg.

When will this drug be available?

Januvia is now available for use in the UK.

How much will it cost?

The cost to the NHS is expected to be in the region of thirty five pounds for a months treatment.

Is it available on the NHS?

This may vary from region to region. Until the drug is approved for use by the Primary Care Trust in your area it may not be prescribed by your doctor.

Manufacturer’s details:

Merck Sharp & Dohme Ltd
Hertford Road
EN11 9BU


Dr Nishan Wijenaike MD, FRCP
Consultant Physician (Diabetes and Endocrinology)
West Suffolk Hospital NHS Trust
Bury St Edmunds
June 2007


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