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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.
  • Treat the clear fluid days like a sick day. Use List 1 or 2 on the next page 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 sugar drops below 4.0 mmol/L or if you have symptoms of low blood sugar, take 15 grams of a carbohydrate-containing fluid from List 1. Test your blood sugar again in 15 minutes. If your blood sugar is still low, take another 15 grams of carbohydrate-containing fluid from List 1.
  • If you’re worried your blood sugar 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 (e.g., apple, white grape)
  • ¾ cup (175 mL) regular pop
  • 1 cup (250 mL) sports drinks (e.g., Gatorade®)
  • water
  • clear bouillon, broth, or consommé
  • diet pop
  • diet Kool-Aid® or Crystal-Lite®
  • black coffee or tea
  • diet popsicle
  • diet Jell-O®

Testing your blood sugar

Test your blood sugar anytime you feel your blood sugar is low or high.

  • Test your blood sugar at least every 4 hours. Blood sugars 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 type 1 diabetes or you are on an SGLT2 inhibitor canagliflozin (Invokana), dapagliflozin (Forxiga), empagliflozin (Jardiance) and ertugliflozin (Steglatro) and your sugars are 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 sugar 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 ertugliflozin (Steglatro)] 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 ertugliflozin (Steglatro)] 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 (Apidra, Humalog, NovoRapid, Fiasp, Humulin R, or Novolin Toronto) 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 sugar becomes low. Your dose will be __________ units.
  • Premix Insulin: Reduce your dose of supper premix insulin (Humulin 30/70, Novolin 30/70, or Humalog 25/75) 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 sugar. If there are no concerns, keep the same basal rate.

Test day

Morning

  • Bolus (meal) Insulin: Don’t take your morning meal (bolus) insulin (Apidra, Humalog, NovoRapid, Fiasp, Humulin R, or Novolin Toronto).
  • Premix Insulin: Don’t take your morning premix insulin (Humulin 30/70, Novolin 30/70, or Humalog 25/75).
  • 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 sugar. 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, Novolin 30/70, or Humalog 25/75) 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: October 15, 2021

Author: Endocrinology and Metabolism Program, Alberta Health Services

Care instructions may be adapted by your healthcare provider. If you have questions about a medical condition or this instruction, talk with your doctor or appropriate healthcare provider.