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sitagliptin

JanuviaDPP-4 inhibitor

Januvia (sitagliptin) is an oral DPP-4 inhibitor from Merck that improves blood sugar control in adults with type 2 diabetes. It is used alone or with metformin, a sulfonylurea, a thiazolidinedione, or insulin when diet and exercise are not enough.

This page is based on the EMA medicine record for sitagliptin, cross-checked with MedlinePlus and the National Cancer Institute dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.

How it works

Explains what the medicine does in the body, not dosing, side effects, or safety.

An analogy

After a meal the gut releases incretin hormones that tell the pancreas to handle the incoming sugar, but an enzyme called DPP-4 shreds them within minutes. Sitagliptin blocks the shredder. The incretin signal lasts longer, so the pancreas releases insulin at the right time and the liver makes less sugar, lowering blood glucose mainly when it is high.

In simple terms

Sitagliptin belongs to the DPP-4 inhibitor class. It blocks dipeptidyl peptidase-4, the enzyme that breaks down incretin hormones such as GLP-1. With DPP-4 inhibited, these natural substances stay active longer, increasing the amounts that lower blood sugar when it is high. This helps the pancreas release insulin and reduces sugar production, improving blood sugar control in adults with type 2 diabetes. Sitagliptin is not used to treat type 1 diabetes.

In depth

Sitagliptin phosphate is an orally available, competitive, beta-amino acid-derived inhibitor of dipeptidyl peptidase-4 (DPP-4) with hypoglycemic activity. By inhibiting DPP-4 it raises active levels of the incretin hormones GLP-1 and GIP, which enhance glucose-dependent insulin secretion from pancreatic beta cells, suppress glucagon secretion, and slow gastric emptying. Because the effect is glucose-dependent, the risk of hypoglycemia is low when sitagliptin is used without insulin or a sulfonylurea. Sitagliptin may be associated with an increased risk of pancreatitis.

See it in motion

A schematic animation of the mechanism — simplified for clarity, not drawn to scale.

How DPP-4 inhibitors work

Dipeptidyl peptidase-4 (DPP-4)sitagliptinthe effect is glucose-dependent
  1. After a meal the gut releases incretin hormones that tell the pancreas to handle the incoming sugar.
  2. An enzyme called DPP-4 shreds them within minutes.
  3. Sitagliptin blocks the shredder, so the pancreas keeps receiving those hormone messages.
  4. The incretin signal lasts longer, so the pancreas releases insulin at the right time and the liver makes less sugar, lowering blood glucose mainly when it is high.
How sitagliptin works

Target: Dipeptidyl peptidase-4 (DPP-4)

The enzyme that rapidly inactivates the incretin hormones GLP-1 and GIP; blocking it prolongs their action so the body releases more insulin and less glucagon when blood sugar is high.

Approved uses

Approved uses differ by country and change over time. Always follow your local prescribing information.

Approved uses in United States

FDA
  • To lower blood sugar levels in adults with type 2 diabetes, as an adjunct to diet and exercise

Approved uses in European Union

EMA
  • As monotherapy, in patients inadequately controlled by diet and exercise alone and for whom metformin is inappropriate due to contraindications or intolerance
  • As dual oral therapy in combination with metformin when diet and exercise plus metformin alone do not provide adequate glycaemic control
  • As dual oral therapy in combination with a sulfonylurea when diet and exercise plus the maximal tolerated dose of a sulfonylurea alone do not provide adequate glycaemic control and metformin is inappropriate due to contraindications or intolerance
  • As dual oral therapy in combination with a peroxisome-proliferator-activated-receptor-gamma (PPAR-gamma) agonist (a thiazolidinedione) when use of the PPAR-gamma agonist is appropriate and diet and exercise plus the PPAR-gamma agonist alone do not provide adequate glycaemic control
  • As triple oral therapy in combination with a sulfonylurea and metformin when diet and exercise plus dual therapy with these medicinal products do not provide adequate glycaemic control
  • As triple oral therapy in combination with a PPAR-gamma agonist and metformin when use of a PPAR-gamma agonist is appropriate and diet and exercise plus dual therapy with these medicinal products do not provide adequate glycaemic control
  • As add-on to insulin, with or without metformin, when diet and exercise plus a stable dose of insulin do not provide adequate glycaemic control

Official sources

The statements on this page trace back to these records.

  1. Januvia (sitagliptin) — Summary of product characteristics and package leaflet, English version

    European Medicines Agency

  2. MedlinePlus: sitagliptin

    MedlinePlus, U.S. National Library of Medicine

  3. National Cancer Institute: sitagliptin phosphate

    National Cancer Institute

This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.

MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.