Diabetes: Adjusting your medicine and diet for a barium enema or colonoscopy
Diabetes
Adjusting your diabetes medicine and diet for a barium enema or colonoscopy
The guidelines below will help you adjust your diabetes medicine and diet as you get ready for your test.
If you see a diabetes educator or diabetes specialist, contact them at least 1 week before your test to ask about adjusting your diabetes medicine or insulin.
Diet
Follow the instructions the gastroenterology (GI) clinic gives you about what you can eat or drink before the test.
Remember, do not eat or drink any of the following:
milk products or substitutes such as soy, almond or goats milk
meal replacements like Boost or Ensure
alcohol
- Treat the clear fluid days like a sick day. Use List 1 or 2 in the table below to choose what to eat and drink. Your diet can be changed to clear fluids in one of these ways:
- If you count carbohydrates, try to drink the same amount of carbohydrates as you would eat at each meal and snack.
- If you follow a meal pattern, any item from List 1 will replace 1 serving from the grains and starches, fruit, milk and alternatives, or other choices group.
- If you don’t follow a special diet or meal plan, eat or drink 1 item from List 1 every hour.
- If your blood glucose (sugar) drops below 4.0 mmol/L or if you have symptoms of low blood glucose, take 15 grams of a carbohydrate-containing fluid from List 1. Test your blood glucose again in 15 minutes. If your blood glucose is still low, take another 15 grams of carbohydrate-containing fluid from List 1.
- If you’re worried your blood glucose will run too low, take extra fluid from List 1.
List 1 - Fluids that have sugar. Each has about 15 grams of carbohydrates. No fluids with red or purple dye. | List 2 - Fluids that are sugar-free. Choose as desired. No fluids with red or purple dye. |
- black tea, coffee, or water with 1 rounded tablespoon (15 mL) sugar or honey
- ½ cup (125 mL) regular Jell-O
- ½ cup (125 mL) regular (sugar sweetened) Kool-Aid
- ¾ cup (175 mL) fruit drink or fruit juice without pulp (such as apple, white grape)
- ¾ cup (175 mL) regular pop (such as ginger ale)
- 1 cup (250 mL) sports drinks (e.g., Gatorade)
- 1 and 1/2 (50 mL) juice popsicle
| - water
- clear bouillon, broth, or consommé
- diet pop (such as diet ginger ale)
- diet Kool-Aid or Crystal-Lite
- black coffee or tea
- diet popsicle
- diet Jell-O
|
Testing your blood glucose
Test your blood glucose anytime you feel your blood glucose is low or high.
- Test your blood glucose at least every 4 hours. Blood glucose in the range of 8.0 to 12.0 mmol/L are fine for these 2 days, even if it’s higher than your usual target.
- If you have type 1 diabetes or you are on an SGLT2 inhibitor - canagliflozin (Invokana), dapagliflozin (Forxiga), empagliflozin (Jardiance) - and combination medicines that contain any of these medicines (such as with metformin) and your glucose is over 14.0 mmol/L, test your urine or blood for ketones.
- If you have type 1 diabetes and are positive for ketones, you may need extra insulin.
- Moderate to large ketones may mean that you’re in DKA (diabetic ketoacidosis). Go to the emergency department right away.
- If you’re worried about your blood glucose level, speak with your healthcare provider or diabetes educator.
Adjusting your diabetes medicine
If You Take Diabetes Medicine other than Insulin
2 Days before the Test
- If you are on an SGLT2 inhibitor - (canagliflozin (Invokana), dapagliflozin (Forxiga), empagliflozin (Jardiance) - or combination medicines that contain any of these medicines (such as with metformin), do not take.
- Take your other diabetes medicine as usual.
The Day Before the Test
- If you are on an SGLT2 inhibitor - (canagliflozin (Invokana), dapagliflozin (Forxiga), empagliflozin (Jardiance) - or combination medicines that contain any of these medicines (such as with metformin), do not take.
- Take your other diabetes medicine as usual or as your healthcare provider tells you.
- If you are on repaglinide (Gluconorm), gliclazide (Diamicron, Diamicron MR) or glyburide (Diabeta), speak to your healthcare provider as your dose(s) may need to be lowered.
Test Day
- Don’t take any diabetes medicine until after your test is done and you’re eating. Then take it as per your scheduled dose.
*Be sure to bring a source of fast-acting sugar and your blood glucose meter with you.
If You Take Insulin The day before the test |
Morning- Basal Insulin: Reduce your dose of basal insulin (Humulin N, Novolin NPH, Lantus, Basaglar, Toujeo, Levemir or Tresiba) by 20% or the amount your healthcare provider tells you. Tresiba may need to be reduced for 2-3 days before the procedure. Talk with your healthcare provider.
Your dose will be __________ units. - Premix Insulin: Reduce your dose of premix insulin (Humulin 30/70, Novolin 30/70, or Humalog 25/75) by 20% or the amount your healthcare provider tells you for your breakfast meal. Your dose will be __________ units.
- Insulin Pump: Keep the same basal rate.
Meals
- Bolus (meal) Insulin: Reduce your dose of bolus (meal) insulin (Admelog, Apidra, Fiasp, Humalog, Humulin R, NovoRapid, Novolin Toronto, or Trurapi) by 20% or the amount your healthcare provider tells you. You may need to reduce your dose of these meal insulins more if your blood glucose becomes low. Your dose will be __________ units.
- Premix Insulin: Reduce your dose of supper premix insulin (Humulin 30/70, Humalog 25/75, Humalog Mix 50, Novolin 30/70, Novolin 40/60, Novolin 50/50) by 20% or the amount your healthcare provider tells you. Your dose will be __________ units.
Evening/Bedtime- Basal Insulin: Reduce your dose of basal insulin (Humulin N, Novolin NPH, Lantus, Basaglar, Toujeo, Levemir or Tresiba) by 20% or the amount your healthcare provider tells you. Tresiba may need to be reduced for 2-3 days before the procedure. Talk with your healthcare provider.
Your dose will be __________ units. - Insulin Pump: You may need to reduce your basal rate by 10% to 20% overnight if there are concerns about low blood glucose. If there are no concerns, keep the same basal rate.
|
Test day |
Morning- Bolus (meal) Insulin: Don’t take your morning meal (bolus) insulin (Admelog, Apidra,Fiasp, Humalog, Humulin R, NovoRapid, Novolin Toronto, or Trurapi).
- Premix Insulin: Don’t take your morning premix insulin (Humulin 30/70, Humalog 25/75, Humalog Mix 50, Novolin 30/70, Novolin 40/60, Novolin 50/50).
- Basal Insulin: Reduce your dose of basal insulin (Humulin N, Novolin NPH, Lantus, Basaglar, Toujeo, Levemir or Tresiba) by 20% or the amount your healthcare provider tells you. Tresiba may need to be reduced for 2-3 days before the procedure. Talk with your healthcare provider.
Your dose will be __________ units. - Insulin Pump: You may need to reduce your basal rate by 10% to 20% overnight if there are concerns about low blood glucose. If there are no concerns, keep the same basal rate.
*Be sure to bring a source of fast-acting sugar and your blood glucose meter with you. After the test- Premix Insulin: Reduce your morning dose of premix insulin (Humulin 30/70, Humalog 25/75, Humalog Mix 50, Novolin 30/70, Novolin 40/60, Novolin 50/50) by 20% or the amount your healthcare provider tells you for your first meal after the test. Your dose will be __________ units.
- All other insulin: Take as prescribed.
*Be sure to bring a source of fast-acting sugar and your blood glucose meter with you. |
To see this information online and learn more, visit MyHealth.Alberta.ca/health/pages/conditions.aspx?Hwid=custom.ab_diabetes_bariumenema_colonoscopy.

For 24/7 nurse advice and general health information call Health Link at 811.
Current as of: June 10, 2022
Author: Endocrinology and Metabolism Program, Alberta Health Services
This material is not a substitute for the advice of a qualified health professional. This material is intended for general information only and is provided on an "as is", "where is" basis. Although reasonable efforts were made to confirm the accuracy of the information, Alberta Health Services does not make any representation or warranty, express, implied or statutory, as to the accuracy, reliability, completeness, applicability or fitness for a particular purpose of such information. Alberta Health Services expressly disclaims all liability for the use of these materials, and for any claims, actions, demands or suits arising from such use.