Canagliflozin with metformin

How it works

Canagliflozin lowers the renal glucose reabsorption threshold to promote urinary glucose excretion, while metformin reduces hepatic glucose output and improves peripheral insulin sensitivity.

Prescribing in practice

• The most important safety point is risk of euglycaemic diabetic ketoacidosis from the SGLT2 component and lactic acidosis from metformin; withhold during acute illness, dehydration, sepsis or surgery (sick-day rules) and avoid in significant renal impairment.
• Canagliflozin carries an increased risk of lower-limb amputation and of genital mycotic and urinary infections, including rare Fournier's gangrene.
• Both components are contraindicated or restricted below defined renal thresholds, so confirm renal function meets the SPC criteria before starting and periodically thereafter.

Monitoring

Monitor renal function, HbA1c, volume status and weight, and remain alert for ketoacidosis symptoms even when blood glucose is near-normal.

Counselling the patient

• Stop the tablets and seek urgent medical advice if you become acutely unwell, dehydrated, or develop nausea, vomiting, abdominal pain or breathlessness.
• Maintain good genital hygiene and report any genital soreness, itching, or signs of foot infection promptly.
• Take with food to reduce stomach upset from the metformin component.

Evidence & guidelines

SGLT2 inhibitors are recommended by NICE in type 2 diabetes, and the CANVAS programme established both cardiovascular benefit and the amputation signal for canagliflozin.