SGLT2 inhibitors: stop before elective surgery per local policy (euglycaemic DKA risk). Never omit basal insulin in type 1.
Pre-op assessment
- HbA1c, recent hypoglycaemia, complications
- Medicines list: insulin, sulfonylurea, SGLT2, GLP-1
- Morning surgery preferred for insulin users
Typical targets (local)
- Aim 6 to 10 mmol/L intraop where safe
- Avoid <4 and >12 mmol/L when possible
- Variable rate insulin infusion if type 1 or long NPO
6 to 10 mmol/L
- Continue the plan
- Hourly monitoring if fasting
- Morning list preferred
Under 6 or over 12
- Treat hypoglycaemia with glucose
- Start VRIII per protocol
- Avoid under 4 and over 12
Ketosis / euglycaemic DKA
- Check ketones if SGLT2 taken
- Never omit basal insulin
- Senior diabetes input
Day of surgery
1
1. Morning meds
Hold metformin and SGLT2 on day of surgery. Reduce or omit sulfonylurea. Give 50 to 80% basal insulin (local protocol) if normally AM dose.
Hold metformin and SGLT2 on day of surgery. Reduce or omit sulfonylurea. Give 50 to 80% basal insulin (local protocol) if normally AM dose.
↓
2
2. Fasting
Check BM on arrival and hourly until eating. Start VRIII if trusts protocol triggers.
Check BM on arrival and hourly until eating. Start VRIII if trusts protocol triggers.
↓
3
3. Intraop
Point-of-care glucose every 1 to 2 h if not on infusion. Treat hypo with glucose gel/IV.
Point-of-care glucose every 1 to 2 h if not on infusion. Treat hypo with glucose gel/IV.
↓
4
4. Post-op
Restart oral agents when eating and renal function stable. SGLT2 only when ketosis excluded.
Restart oral agents when eating and renal function stable. SGLT2 only when ketosis excluded.
Type 1 essentials
- Never stop basal insulin
- VRIII with glucose-potassium infusion paired
Pitfalls
- Omitting all insulin on NPO type 1
- Restarting metformin with AKI
MedPrep - www.medprep.uk - Educational revision aid only. Not clinical guidance. Doses are adult examples; check the BNF, current guidelines and local policy, and seek senior advice. Nov 2026