Incretin-based agents · Endocrine
Sitagliptin
Januvia®(brand names vary by market)
A quiet, well-tolerated oral agent that does not cause hypoglycemia.
Mechanism
Inhibits dipeptidyl peptidase-4, the enzyme that degrades native GLP-1 and GIP. Because the incretin effect is glucose-dependent, insulin only rises when glucose is high.
Indications
- Type 2 diabetes
Formulations
Dosing concepts
Renal impairment
Renally cleared, so the dose is reduced in stages as eGFR falls. This is one of the commonest missed dose adjustments in diabetes prescribing.
Combination
Never combined with a GLP-1 receptor agonist: the agonist already saturates the pathway the inhibitor was protecting.
Concepts, not prescribing instructions. Practice numbers live in current references and local protocols.
Pharmacokinetics
- Bioavailability
- ~87%
- Half-life
- ~12 h
- Elimination
- renal: Mostly excreted unchanged; minimal CYP involvement and few interactions
- Protein binding
- Low
Adverse effects
- Nasopharyngitis and headachecommon
- PancreatitisseriousRare; persistent severe abdominal pain warrants stopping and investigation.
- Severe joint painseriousA class warning; it can appear at any point and resolves on stopping.
- Bullous pemphigoidseriousUncommon but well described with the class.
Contraindications & precautions
Contraindications
- Type 1 diabetes
- Diabetic ketoacidosis
Precautions
- History of pancreatitis
- Renal impairment (dose adjustment)
- Heart failure with some members of the class
Interactions
No curated interaction entries yet for this agent.
Monitoring
HbA1c
Efficacy; the effect is modest and should be judged honestly
Renal function
Drives the dose
Persistent abdominal or joint pain
The two class-specific harms worth asking about
Counselling points
- Once daily, with or without food.
- It does not usually cause low blood sugars on its own.
- Report severe abdominal pain that does not settle, or severe joint pain.
Clinical pearls
- It lowers HbA1c modestly and has no cardiovascular or renal outcome benefit, which is why guidelines have moved it behind SGLT2 inhibitors and GLP-1 agonists for anyone with cardiac or renal disease.
- Its virtue is tolerability: for a frail patient in whom hypoglycemia is the main danger, that is a real argument.
References & review
- Sitagliptin product monograph (consult the current version for your market) (monograph)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)
Last reviewed 2026-08-16 · jurisdiction: global · drug information changes; verify against current references before practice use.