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Instructions for Patients with Diabetes

These are general guidelines. Please call the health care provider who manages your diabetes for questions. For people with diabetes, any procedure that causes you to miss a meal or change your usual meal plan will require special planning to safely manage blood glucose.

Insulin and Diabetes Pills: If you are a diabetic, it is important to monitor your blood sugar while doing the bowel preparation. You should take only ½ of your usual dose of insulin or pills on your prep day. You should not take any diabetic medications on the day of your procedure. Please be sure to check your blood sugar at home at all meals, at bedtime and on the morning of your exam.

Examination scheduling tips

  • Schedule the appointment for early in the day so that you can eat afterwards and take your medication as close to the usual time as possible.
  • Check your blood glucose level before all meals and at bedtime on the preparation day and on the day of the procedure.
  • Check your blood glucose if at any time you have symptoms of low blood glucose or very high blood glucose.
  • Bring your blood glucose meter, test strips, and a low blood glucose treatment with you on the day of the procedure. Clear liquid food choices for the day before your colonoscopy:
    • Aim for 45 grams of carbohydrate at meals and 15-30 grams of carbohydrate for snacks.
    • Avoid foods that are red or have red dyes (cherry, berry, or grape flavors).

Examples of clear liquid choices with carbohydrates

  • Apple juice (4 ounces) - 15 grams carbohydrates
  • White grape juice (4 ounces) - 20 grams carbohydrates
  • Sports drink such as Gatorade (8 ounces) - 14 grams carbohydrates
  • Gelatin (Jello), regular sweetened (1/2 cup) - 15 grams carbohydrates
  • Orange popsicles or ice pops (read the label) - 15 grams carbohydrates
  • Italian ice--not sherbet (read the label) - 30 grams carbohydrates
  • Sugar (for coffee or tea) (1 teaspoon or packet) - 4 grams carbohydrates

Food items without carbohydrates

  • Fat-free broth, bouillon, or consomme
  • Diet clear soda
  • Coffee
  • Tea, unsweetened or diet
  • Seltzer
  • Flavored water

View these instructions as a printable PDF

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