What it's for (Indications)
- Sitagliptin (e.
- g.
- , Sita) is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.
- It can be utilized as a monotherapy when metformin is inappropriate or not tolerated.
- Furthermore, sitagliptin is approved for use in combination therapy with other antihyperglycemic agents, including metformin, sulfonylureas, thiazolidinediones (TZDs), insulin, and glitazones, to achieve adequate blood sugar management.
- Its therapeutic role is strictly limited to type 2 diabetes and does not extend to type 1 diabetes or diabetic ketoacidosis.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | The recommended dose of sitagliptin is 100 mg orally once daily. This can be taken with or without food. Dosage adjustments are crucial for patients with renal impairment to prevent drug accumulation and potential adverse effects. For patients with moderate renal impairment (creatinine clearance [CrCl] ≥30 to <50 mL/min), the recommended dose is 50 mg once daily. In cases of severe renal impairment (CrCl <30 mL/min) or end-stage renal disease (ESRD) requiring dialysis, the recommended dose is 25 mg once daily. It is essential to assess renal function prior to initiating treatment and periodically thereafter. |
Safety & Warnings
Common Side Effects
- Commonly reported adverse reactions associated with sitagliptin include nasopharyngitis, headache, and upper respiratory tract infections.
- Less frequent, but potentially serious, adverse effects include acute pancreatitis (which can be severe, hemorrhagic, or necrotizing), serious hypersensitivity reactions such as anaphylaxis, angioedema, and severe cutaneous adverse reactions like Stevens-Johnson syndrome.
- Other notable adverse events include bullous pemphigoid, severe and disabling arthralgia (joint pain), and hypoglycemia, particularly when sitagliptin is co-administered with a sulfonylurea or insulin.
- Acute renal failure and worsening renal function have also been reported in postmarketing surveillance.
Serious Warnings
- Black Box Warning: Sitagliptin does not carry a formal FDA Black Box Warning. However, several serious warnings and adverse reactions have been reported that warrant careful consideration by healthcare professionals and patients: **Serious Warnings:** * **Pancreatitis:** Postmarketing reports have described cases of acute pancreatitis, including fatal and nonfatal hemorrhagic or necrotizing pancreatitis, in patients taking sitagliptin. Patients should be informed of the characteristic symptom of acute pancreatitis: persistent, severe abdominal pain that may radiate to the back, with or without vomiting. If pancreatitis is suspected, sitagliptin should be promptly discontinued, and appropriate management initiated. * **Hypersensitivity Reactions:** Serious hypersensitivity reactions, such as anaphylaxis, angioedema, and severe cutaneous adverse reactions (e.g., Stevens-Johnson syndrome), have been reported with sitagliptin. These reactions can occur rapidly after initiation of treatment, even after the first dose. If a hypersensitivity reaction is suspected, discontinue sitagliptin and do not restart. * **Bullous Pemphigoid:** Postmarketing cases of bullous pemphigoid requiring hospitalization have been reported with DPP-4 inhibitor use, including sitagliptin. If bullous pemphigoid is suspected, sitagliptin should be discontinued. * **Severe Arthralgia:** Severe and disabling joint pain (arthralgia) has been reported in patients taking DPP-4 inhibitors. The onset of symptoms following initiation of drug therapy was variable. Consider sitagliptin as a possible cause for severe joint pain and discontinue if appropriate.
- Several important warnings and precautions should be considered during sitagliptin therapy.
- Renal function should be assessed prior to initiating treatment and monitored periodically, especially in elderly patients and those with known renal impairment, as dose adjustments are necessary.
- When sitagliptin is used in combination with an insulin secretagogue (e.
- g.
- , sulfonylurea) or insulin, the risk of hypoglycemia is increased, and a dose reduction of the concomitant agent may be required.
- There have been postmarketing reports of severe and disabling arthralgia, which may warrant discontinuation of the drug.
- While a definitive causal link to heart failure has not been established for sitagliptin in major cardiovascular outcomes trials, some other drugs in the DPP-4 inhibitor class have shown an increased risk of heart failure hospitalization, thus caution is advised in patients with heart failure risk factors.
- Sitagliptin is not indicated for type 1 diabetes or diabetic ketoacidosis.
How it Works (Mechanism of Action)
Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that enhances glycemic control in patients with type 2 diabetes mellitus. It functions by inhibiting the enzymatic activity of DPP-4, an enzyme responsible for the rapid degradation of the incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). By preventing the breakdown of these endogenous incretins, sitagliptin increases their active concentrations in the circulation. This leads to enhanced glucose-dependent insulin secretion from pancreatic beta cells and a reduction in glucagon secretion from pancreatic alpha cells. The net effect is an improvement in both fasting and postprandial glucose levels, with a lower risk of hypoglycemia compared to agents that stimulate insulin release regardless of glucose levels.