Sitagliptin (Januvia) is an oral antidiabetic drug of the dipeptidyl peptidase-4 (DPP-4) inhibitor class indicated alone or in combination with other oral antihyperglycemic agents for treatment of diabetes mellitus type 2
 BRAND NAMES
 MECHANISM OF ACTION
Incretin hormones such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are released into the bloodstream from the small intestine in response to meals.
These hormones cause insulin release from the pancreatic beta cells in a glucose-dependent manner but are inactivated by the Dipeptidyl peptidase-4 (DPP-4) enzyme within minutes.
GLP-1 also lowers glucagon secretion from pancreatic alpha cells, reducing hepatic glucose production.
In patients with type 2 diabetes, concentrations of GLP-1 are reduced but the insulin response to GLP-1 is preserved.
Sitagliptin is a Dipeptidyl peptidase-4 inhibitor (DPP-4 inhibitor) that slows the inactivation of the incretin hormones, thereby increasing their bloodstream concentrations and reducing fasting and postprandial glucose concentrations in a glucose-dependent manner in patients with type 2 diabetes mellitus.
Sitagliptin is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus:
- as monotherapy, in patients inadequately controlled by diet and exercise alone and for whom metformin is inappropriate due to contraindications or intolerance.
- In dual combination with one of metformin, a sulfonylurea or a thiazolidinedione when diet, exercise and the single agent do not result in adequate glycemic control.
- In triple combination:
Sitagliptin should not be used in patients with type 1 diabetes or for the treatment of diabetic ketoacidosis.
100 mg once daily, with or without food.
Patient with renal impairment should use a lower dosage
 DOSAGE FORMS AND STRENGTHS
Tablets: 100 mg, 50 mg, and 25 mg
History of a serious hypersensitivity reactions to Sitagliptin or to any dipeptidyl peptidase 4 (DPP4) inhibitor. These reactions include anaphylaxis, angioedema, and severe cutaneous adverse reactions including Stevens-Johnson syndrome.
 WARNINGS AND PRECAUTIONS
- There have been postmarketing reports of acute pancreatitis, including fatal and non-fatal hemorrhagic or necrotizing pancreatitis. Patients should be observed for signs and symptoms of pancreatitis. If pancreatitis is suspected, promptly discontinue Sitagliptin.
- Hypersensitivity reactions: There have been postmarketing reports of serious hypersensitivity reactions in patients treated with Sitagliptin. These reactions include anaphylaxis, angioedema, and severe cutaneous adverse reactions including Stevens-Johnson syndrome. If a serious hypersensitivity reaction is suspected, discontinue the drug. Use also with caution in patients with a history of angioedema to another DPP-4 inhibitor
- Acute renal failure: There have been postmarketing reports of acute renal failure, sometimes requiring dialysis, in patients treated with sitagliptin. Assessment of renal function is recommended prior to initiation of Sitagliptin and periodically thereafter.
- A lower dose of Insulin secretagogue, (e.g., sulfonylurea) or insulin dosage when used in combination with Sitagliptin may be required to minimize the risk of hypoglycemia
 PREGNANCY AND LACTATION
- Pregnancy Category B (US). Sitagliptin like other antidiabetic medications, should be used during pregnancy only if clearly needed
- It is not known whether Sitagliptin is secreted in human milk. Caution should be exercised when it is administered to a nursing woman
 SIDE EFFECTS
Possible side effects include reported in ≥5% of patients are: upper respiratory tract infection, nasopharyngitis and headache. In dual and triple therapy hypoglycemia was commonly reported.
 RELATED LINKS
|Diabetes (Antidiabetic drugs)|
|Insulin Secretagogues (drugs that increase insulin release from pancreas)||Sulfonylureas||Chlorpropamide (Diabinese) • Glibenclamide or Glyburide (Diabeta, Micronase, Glynase, Daonil, Euglycon) • Gliclazide (Diamicron) • Glimepiride (Amaryl, Solosa) • Glipizide (Glucotrol, Minidiab, Glibenese) • Gliquidone (Glurenorm)|
|Meglitinides||Repaglinide (Prandin, Novonorm) • Nateglinide (Starlix)|
|Dipeptidyl peptidase-4 inhibitors||Linagliptin (Trajenta) • Saxagliptin (Onglyza) • Sitagliptin (Januvia) • Vildagliptin (Galvus)|
|Incretin mimetics (GLP-1 agonists and analogs)||Exenatide (Byetta) • Liraglutide (Victoza) • Lixisenatide (Lyxumia) • Dulaglutide (Trulicity)|
|Insulin Sensitizers (drugs that decrease insulin resistance)|
|Drugs that retard the digestion and absorption of carbohydrates in the small intestine|
|Alpha-glucosidase inhibitors||Acarbose (Glucobay, Precose)|
|Drugs that reduce glucose absorption in the kidney and increase glucose excretion in the urine|
|Sodium glucose cotransporter 2 (SGLT2) inhibitors||Canagliflozin (Invokana) • Dapagliflozin (Farxiga) • Empagliflozin (Jardiance, Glyxambi, Synjardi)|
|Insulin and insulin analogs|
|Intermediate acting insulins||Insulin lispro protamine (Humalog BASAL) • Isophane human insulin : Human insulin protamine (NPH) (Humulin I, Protaphane)|
|Long-acting insulins||Insulin detemir (Levemir) • Insulin glargine (Lantus)|
|Fast-acting insulins||Regular insulin : Insulin (Human recombinant) (Actrapid, Humulin R)|
|Ultra-rapid-acting insulins||Insulin aspart (Novorapid) • Insulin glulisine (Apidra) • Insulin lispro (Humalog) • Insulin human (Inhalation Powder) (Afrezza)|
|Premixed insulin (ultra-rapid-acting + intermediate acting||Insulin aspart / Insulin aspart protamine (Novomix) • Insulin lispro / Insulin lispro protamine (Humalog Mix)|
|Inhaled Insulin||Insulin human (Inhalation Powder) (Afrezza)|
|Sulfonylurea + Metformin||Glibenclamide / Metformin (Bieuglicon M, Diaglimet, Glibomet, Gliconorm, Glicorest, Suguan M)|
|Thiazolidinedione + Metformin||Pioglitazone / Metformin (Competact, Glubrava)|
|Thiazolidinedione + Sulfonylurea||Pioglitazone / Glimepiride (Tandemact)|
|Dipeptidyl peptidase-4 inhibitors + Metformin||Linagliptin / Metformin (Jentadueto) • Sitagliptin / Metformin (Efficib, Janumet, Velmetia) • Vildagliptin / Metformin (Eucreas)|