Blood Sugar Monitoring

If you usually test your blood sugar levels, check them, as usual, on the morning of the procedure and bring your monitoring equipment with you to the appointment. 

If you do not usually test your blood, do not worry, your blood levels will be checked when you arrive for the procedure.

People taking diabetes tablets

Day before colonoscopy – clear fluids only

Aim to have carbohydrate at your usual meal times from the list of permitted clear fluids. You can have sugary fluids, fruit juice or fruit jelly to replace your usual carbohydrates

• If taking Metformin do not take until you are eating again after the colonoscopy 
• If taking Rosiglitazone (Amaryl) or Pioglitazone (Starlix) do not take until after the colonoscopy. 
• If taking Gliclazide, Glibenclamide, Tolbutamide, Repaglanide or Glimepiride take half your morning dose and do not take again until after the test.

The day of the colonoscopy

• Do not take your morning dose of tablets; bring your tablets with you to have after the procedure 
•  Report to the nursing staff if you have needed glucose before arriving and inform them immediately if you feel ‘hypo’ at any time during your visit 
• Your dosage of tablets can be given as soon as you are able to eat and drink safely; the nursing staff will inform you when this is safe.

People on insulin

Day before the colonoscopy

• Aim to have carbohydrate at your usual meal times using fluids from the list of permitted clear fluids. 
• You will need to reduce your usual insulin doses to avoid the risk of hypoglycaemia (low blood sugar). You should reduce each of your insulin doses by at least a third except if taking Lantus or Levemir. This should be continued at the normal dose.
•  If you have concerns about adjusting your insulin dosage please contact the Diabetes Nursing Team well in advance of the appointment to discuss appropriate measures.

Day of the colonoscopy

• Do not take your morning dose of insulin; bring your insulin with you to have after the procedure. n If you take Lantus or Levemir continue your normal dose 
• Report to the nursing staff if you have needed glucose before arriving and inform them immediately if you feel ‘hypo’ at any time during your visit. 
• Your morning dose of insulin can be given as soon as you are able to eat and drink safely; the nursing staff will inform you when this is safe.