Sitagliptin with metformin

How it works

Sitagliptin inhibits DPP-4 to prolong incretin action, enhancing glucose-dependent insulin secretion and suppressing glucagon, while metformin lowers hepatic glucose output and improves insulin sensitivity.

Prescribing in practice

• The metformin component requires renal function review and temporary withholding during acute illness, dehydration, or before iodinated contrast procedures, owing to the rare risk of lactic acidosis.
• Sitagliptin may rarely precipitate acute pancreatitis and hypersensitivity reactions; discontinue if pancreatitis is suspected.
• Metformin frequently causes gastrointestinal side effects, reduced by taking with food and considering a modified-release preparation.

Monitoring

Monitor renal function and HbA1c, with review of gastrointestinal tolerance and any features suggesting pancreatitis.

Counselling the patient

• Take with or after food to limit stomach upset.
• Stop temporarily and seek advice if you become severely unwell or dehydrated, or before a contrast scan.
• Report severe or persistent abdominal pain to your team.

Evidence & guidelines

NICE positions metformin as first-line therapy for type 2 diabetes, with DPP-4 inhibitors such as sitagliptin as established options for treatment intensification.