Management of Diabetes Undergoing Elective Surgery

Patient Information Leaflet

These instructions are for patients with diabetes treated with premixed insulin, for example, novomix 30, humalog mix25, humalog mix50, or humulin M3.

On the day before surgery

If you are on a SGLT2 inhibitor (examples are dapaglifozin, empagliflozin or canagliflozin), stop these drugs. Resume only after your operation when you are eating and drinking normally.

Continue your usual diabetic medications and follow any bowel preparations as advised by your surgeon / staff at the pre-assessment clinic.

On the day of surgery

Please take half of your usual morning dose of premixed insulin.

The following medications should be stopped from time of fasting:

• Sulphonylurea – examples are gliclazide, glimepiride and tolbutamide.
• Rapaglinide.
• SGLT2 inhibitors – examples are dapagliflozin, canagliflozin and empagliflozin.

Under special circumstances, your metformin may need to be withheld for 48 hours. Staff from the pre-assessment team will inform you of this.

Your other diabetic medications can continue on the morning of your operation.

Remember to bring to hospital all of your diabetes medications, dextrose tablets and blood testing equipment.

When you arrive at hospital your blood glucose will be tested by finger prick and then monitored regularly. You can ask for extra blood testing if you feel symptoms of a ‘hypo’ (low blood glucose).

The target for safe surgery is 6 – 10 mmol. You may need insulin treatment to bring down high glucose, or dextrose infusion for treatment of low blood glucose.

After surgery

You will be discharged when you are eating and drinking normally and your blood glucose is at a safe level.

However, if you are unwell with:

• Continuous vomiting / diarrhoea, or high fever
• Unable to keep food down for four hours or more
• High blood glucose (>15.0 mmol by finger prick testing)
• High ketones (>0.6 mmol)

You should seek medical help. During office hours, contact your usual diabetes specialist nurse or doctor.

At other times, contact your local out-of-hours GP service.

If you have any questions, or if there is anything you do not understand about this leaflet, please contact:

The Diabetes and Endocrine Centre on 01384 244399

Russells Hall Hospital switchboard number: 01384 456111

If you have any feedback on this patient information leaflet, please email dgft.patient.information@nhs.net

Originator: Terence Pang, Chris Homer. Date originated: October 2013 Date reviewed: October 2025 Next review date: October 2028 Version: 3 DGH ref: DGH/PIL/00898