This leaflet is for anyone with diabetes (of any type) who is due to have an endoscopy that requires them to have bowel preparation.
This covers:
colonoscopy
sigmoidoscopy
gastroscopy and colonoscopy
gastroscopy and sigmoidoscopy.
Bowel preparation (or ‘Bowel prep’) means completely emptying the bowel before a procedure. This is done by taking medicines to make you go to the toilet, and by cutting down and then stopping food a few days before.
Follow what applies to you
Here we cover how to alter your insulin or other diabetes medication around the time of your appointment to control your blood sugar safely.
If you control your diabetes with diet alone, you do not need to do anything apart from the bowel preparation instructions you have been sent.
Remember
Tell the endoscopy team that you have diabetes. We can then give you an appointment as close to the start of the morning or afternoon as possible. This is to reduce any disruption to your usual insulin or medication regimen.
On the day before and the day of the procedure carry glucose tablets in case of low blood sugar levels. If your blood sugar levels drop (less than 4 mmol/l), see the hypoglycaemia instructions at the end of this document.
If you have had a ‘hypo’ and taken glucose, tell the nurses when you arrive.
If you usually check your blood sugar levels yourself, you should continue to do so, particularly before taking insulin. If you do not usually check them, we will do so when you arrive.
As you cannot eat solid food, replace your carbs with sugary drinks, juices, or jellies.
Day of the appointment
Do not take your morning dose, but bring them with you.
When you can eat and drink after the procedure, take your morning dose.
exenatide
liraglutide (Saxenda, Victoza)
dulaglutide (Trulicity)
Bydureon
semaglutide (Ozempic)
Xultophy
lixisenatide
Day before
Take your dose as normal.
Day of the appointment
Take your dose as normal.
General advice
Contact for advice
For advice about insulin dose adjustments, contact the diabetes nurse team on 020 8934 6370.
Avoiding low blood sugars
Check your blood glucose regularly.
If it drops below 4 mmol/l, have approximately 20g carbohydrate (see Box 1) until your blood glucose is back above 5. You can do this for up to 4 hours before your appointment.
To avoid the risk of low blood sugars, you can have sips of water and/or sips containing carbohydrates until 2 hours before your appointment.
See Box 1 and Box 3 for examples.
Box 1
For approx. 20g carbohydrates
200ml (13 tablespoons) of non-diet cola
OR
4 teaspoons of sugar in 100ml of water
OR
200ml clear apple/grape juice
OR
220ml Lucozade
OR
5 or 6 glucose tablets
Hypoglycaemia
If you have a hypo (hypoglycaemia) during the 4 hours before your appointment, follow the advice in Box 2.
Tell the endoscopy department if this happens.
If your blood glucose does drop below 4 and/or you take glucose, let the endoscopy nurses know when you arrive, or call us if you think that it will be difficult to come for your appointment.
Box 2
Hypo treatment
Step 1
Take 15 to 20g rapid-acting glucose:
5 to 6 dextrose/Lucozade sweets
OR
5 to 6 Glucotabs
OR
150ml to 200ml fruit juice or non-diet cola
OR
one 60ml bottle Glucojuice (Lift)
Step 2
Test glucose after 10 minutes
Repeat step 1 if still below 4.0mmol/L
For type 1 diabetes
Whilst on clear fluids only, aim for 100g to 150g of carbs (carbohydrate) spread over 7 portions during the day.
See Box 3 for fluids that do and do not contain carbohydrates.
Have half your normal amount of quick-acting insulin at your normal times.
Monitor your blood sugars at least every 4 hours during the day.
If you have a hypo, follow the advice in Box 2.
For type 2 diabetes treated with 2 injections a day
Whilst on clear fluids only, aim for 100g to 150g of carbs (carbohydrate) spread over 7 portions during the day.
See Box 3 for fluids that do and do not contain carbohydrates.
Reduce your normal insulin dose by one-third i.e., divide by 3.
Monitor blood sugars every 4 hours.
Box 3
Fluids containing NO carbohydrate:
sugar-free squash
diet fizzy drinks
Bovril, Oxo or Marmite
black Tea and coffee
sugar-free jelly
water.
Fluids containing carbohydrate:
non-diet fizzy drinks have 35g carbs per 330ml can
125g pot ready-made jelly (not sugar-free) has 16g carbs
