sitagliptin
Brand: Januvia
Prototype Drug
Drug Class: DPP-4 inhibitor
Drug Family: antidiabetic
Subclass: dipeptidyl peptidase-4 inhibitor
Organ Systems: endocrine
Mechanism of Action
Inhibits the DPP-4 enzyme responsible for degrading incretin hormones GLP-1 and GIP. By preventing their degradation, sitagliptin prolongs incretin activity, which glucose-dependently stimulates insulin secretion from beta cells and suppresses glucagon from alpha cells, lowering postprandial and fasting glucose.
DPP-4 (dipeptidyl peptidase-4 enzyme)
Indications
- type 2 diabetes mellitus (monotherapy or combination)
Contraindications
- type 1 diabetes
- DKA
- history of pancreatitis (use with caution)
Adverse Effects
Common
- upper respiratory infections
- nasopharyngitis
- headache
Serious
- pancreatitis (rare)
- severe arthralgia (joint pain)
- bullous pemphigoid
- hypersensitivity reactions (angioedema, SJS rare)
Pharmacokinetics (ADME)
| Absorption | oral bioavailability ~87%; not affected by food |
| Distribution | 38% protein bound |
| Metabolism | minimal hepatic metabolism (CYP3A4 and CYP2C8 minor pathways) |
| Excretion | renal (~87% unchanged) |
| Half-life | 12.4 hours |
| Onset | rapid |
| Peak | 1–4 hours |
| Duration | 24 hours |
| Protein Binding | 38% |
| Vd | 198 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| digoxin | P-gp inhibition slightly increases digoxin levels; monitor | minor |
| strong CYP3A4 inhibitors | minor effect on sitagliptin exposure | minor |
Nursing Considerations
- Dose reduction required in moderate (GFR 30–45: reduce to 50 mg) and severe (GFR <30: reduce to 25 mg) renal impairment.
- Instruct patient to report severe and persistent abdominal pain — may indicate pancreatitis, requiring immediate discontinuation.
- Sitagliptin has a low risk of hypoglycemia as a monotherapy because its effect is glucose-dependent (no action at normal glucose levels).
- Assess for joint pain (arthralgia), which has been reported as a serious but reversible adverse effect in some patients.
Clinical Pearls
- DPP-4 inhibitors are weight-neutral (no significant weight change) and have a very low hypoglycemia risk as monotherapy — attributes that make them well-tolerated and popular as second-line agents after metformin.
- The TECOS trial confirmed cardiovascular safety for sitagliptin; unlike GLP-1 agonists, there is no CV benefit beyond safety, but there is also no CV harm.
Safety Profile
Pregnancy use-with-caution
Lactation use-with-caution
Renal Adjustment Required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.