Colonoscopy Preparation (Bowel preparation – Moviprep / Plenvu / Picolax) for People with Diabetes Controlled with Tablets or by Injections of GLP-1 Agonists
Please bring all your diabetic medications into hospital with you and your blood glucose testing kit (if you have one).
If you are driving, wait until your blood glucose level is above 5mmol/L.
Please follow instructions in the table overleaf marked ‘What to do with your medication before procedure’.
Please follow instructions about your bowel prep on diet and fluid intake.
If you have any symptoms of low blood sugar such as sweating, dizziness, blurred vision or shaking, please test your blood sugar. If it is less than 4mmol/L, take 5 glucose tablets or 150ml of apple juice or non-diet lemonade. Please tell staff at the hospital that you have done this as it is possible that your procedure may have to be postponed.
After the procedure
After the procedure your blood glucose will be checked. When you have recovered, you will be offered food and drink. If you are eating and drinking normally later that day, restart your diabetes medications. Please note, your blood glucose levels may be a little unsettled for a day or so.
If you do not improve quickly or if you have any concerns, please phone your GP practice for advice.
What to do with your medication before the procedure
| Medication | Day before admission | Day of procedure | |
| Morning appointments | Afternoon appointment | Morning and afternoon appointments | |
| Acarbose | Take medication with breakfast; omit any further doses once not eating | Take medication if eating meals; stop once not eating | On the day of the procedure, if not eating do not take the medication(s) Restart taking medication(s) as normal when you have a meal after the procedure |
| Repaglinide or nateglinide | Take medication with breakfast; omit any further doses once not eating | Take medication if eating meals; stop once not eating | |
| Metformin | Take medication with breakfast; omit any further doses once not eating | Take medication if eating meals; stop once not eating | |
| Sulphonylureas (e.g. glibenclamide, glipizide, gliclazide, glimepiride) | Take half the morning dose Omit any further doses once not eating | Take half the morning dose If evening dose is taken, half the dose | |
| Pioglitazone | Take medication with breakfast; omit any further doses once not eating | Take medication if eating meals; stop once not eating | |
| DDP-4 inhibitors (e.g. sitagliptin, saxagliptin, linagliptin) | Take medication with breakfast; omit any further doses once not eating | Take medication if eating meals; stop once not eating | |
| SGLT-2 inhibitors (e.g. Dapagliflozin, Canagliflozin, Empagliflozin) | Take medication with breakfast; omit any further doses once not eating | Take medication if eating meals; stop once not eating | |
| GLP-1 agonists (e.g. Ozempic, Semaglutide, Mounjaro, Tirzepatide, Dulaglutide (Trulicity®) | Take as normal | Take as normal | Take as normal |
You should resume taking your normal tablets the morning after the procedure. However, your blood glucose may be higher than usual for a day or so.
About this leaflet
Authors: Dinsdale Marjoram
Written: January 2026
Approved: March 2026
Review date: January 2029
Edition: v1