Linagliptin with metformin

How it works

Linagliptin prolongs the action of incretin hormones to enhance glucose-dependent insulin release and suppress glucagon, while metformin reduces hepatic glucose output and improves peripheral insulin sensitivity.

Prescribing in practice

• The metformin component carries the risk of lactic acidosis, so the combination is contraindicated in significant renal impairment, acute illness with hypoxia or dehydration, and must be withheld around iodinated contrast and major surgery.
• Linagliptin is largely eliminated non-renally, but the combined product is still limited by metformin's renal cut-offs, so monitor eGFR and adjust or stop accordingly.
• Hypoglycaemia is uncommon with these agents alone but increases when combined with a sulfonylurea or insulin, which may need dose reduction.

Monitoring

Monitor HbA1c, renal function and, with long-term metformin, vitamin B12 status, while remaining alert to symptoms of lactic acidosis.

Counselling the patient

• Take with or just after food to reduce stomach upset from the metformin component.
• Stop and seek advice during acute illness with dehydration, vomiting or before procedures using contrast dye.
• Report any unexplained severe abdominal pain, as DPP-4 inhibitors have rarely been linked with pancreatitis.

Evidence & guidelines

DPP-4 inhibitor plus metformin combinations are recommended in NICE type 2 diabetes guidance as a step-up where metformin alone gives inadequate control, with single-tablet products aiding adherence.