Sitagliptin is an oral antihyperglycemic agent used to treat type 2 diabetes. It is a dipeptidyl peptidase-4 (DPP-4) inhibitor. Here’s an overview of its key aspects:

Mechanism of Action:

  • Sitagliptin works by inhibiting the DPP-4 enzyme, which is responsible for breaking down incretin hormones like GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide).
  • By inhibiting DPP-4, sitagliptin increases the levels of these hormones, which in turn:
    • Enhances insulin release from the pancreas in a glucose-dependent manner.
    • Suppresses glucagon secretion, reducing glucose production by the liver.
    • Delays gastric emptying to help regulate blood sugar levels.

Indications:

  • Sitagliptin is used to improve glycemic control in adults with type 2 diabetes mellitus, either as monotherapy or in combination with other antidiabetic medications like metformin, sulfonylureas, or insulin.

Dosage:

  • The typical dose is 100 mg once daily, with or without food.
  • Dosage adjustments may be needed for patients with renal impairment.

Side Effects:

Common side effects include:

  • Upper respiratory tract infections
  • Headache
  • Nasopharyngitis
  • Gastrointestinal symptoms (e.g., nausea, diarrhea)

Rare but serious side effects may include:

  • Pancreatitis (inflammation of the pancreas)
  • Severe allergic reactions (e.g., angioedema)
  • Joint pain
  • Hypoglycemia (when used with other antidiabetic drugs)

Contraindications:

  • Sitagliptin is contraindicated in patients with a history of hypersensitivity to the drug or its components.
  • It is not recommended for type 1 diabetes or diabetic ketoacidosis.

Drug Interactions:

  • Sitagliptin has a low potential for drug interactions but may interact with:
    • Other antidiabetic drugs (increased risk of hypoglycemia)
    • Drugs that affect kidney function (e.g., NSAIDs, ACE inhibitors)

Special Considerations:

  • Renal Impairment: Dose adjustment is required for patients with moderate to severe kidney disease.
  • Pregnancy and Lactation: Use only if the potential benefit justifies the potential risk to the fetus or infant.
  • Elderly Patients: No dose adjustment is needed based on age alone, but renal function should be monitored.

Brand Names:

  • Sitagliptin is marketed under the brand name Januvia and is also available in combination with metformin as Janumet.

Consult a healthcare provider for personalized medical advice and treatment.