Pediatric Gastroenterology
(317) 338-9450
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Colonoscopy Bowel Prep

15–20 kg[33–44 lb]
Lactulose option (oral)
← Other weight bands
Procedure Location
St. Vincent Hospital — Pediatric Preop, Door #1
Pediatric Preop phone: (317) 338-5851
Arrive 90 minutes before your scheduled procedure

📖 About the Procedure

A colonoscopy is a short procedure done under anesthesia. A pediatric gastroenterologist passes a thin, flexible camera through the bottom to look at the large intestine. Small biopsies are usually taken. The procedure itself takes about 20–45 minutes, but plan to be at the facility for several hours total. The colon must be clean for the camera to see well — that's what the medicines below are for.

Plan Ahead (buy at least 2 days before)

Buy these items at least 2 days before the procedure. Check the active ingredient on the label — brand-name shortcuts can lead to the wrong product.

Active ingredient / ItemWhat to get
Lactulose oral solution (10 g per 15 mL) — prescription required
Call the office if you have not received a prescription.
150 mL bottle
enough for big prep with rescue
Bisacodyl 5 mg tablets (Dulcolax Tablets — Overnight Laxative)
⚠️ NOT Dulcolax liquid or soft-chews
1 Dulcolax 5 mg tablet (5 mg total)
Gatorade or Powerade (any color except red or purple) — for mixing with the lactulose At least 32 oz
Skin protection — protective ointment (Desitin or Vaseline) for anal-area comfort 1 tube
⚠️ 💊 Medications

Prepare a list of medications and be ready to discuss them with the nurse or scheduler when they call.
Stop iron, anti-diarrhea medicine 7 days before.
You can verify what medications may need to be stopped at meds.giready.com.

meds.giready.com QR code

⚠️ If any history or suspicion of constipation, please do a pre-cleanout before the regular prep timeline below:

15 mL of lactulose mixed into 4 oz of clear liquid, 2 times daily for 3 days — best done over the weekend before the procedure

Then continue prescribed daily laxatives, or at least 15 mL of lactulose daily, until the procedure.

⚖️ Big-Prep Mix — by Weight

This is the lactulose-in-Gatorade mix your child will drink on prep day. Find your child's weight and mix that amount:

Your Child's WeightLactulose to MixInto Gatorade
15–17 kg (33–37 lb)60 mL20 oz (~600 mL)
18–20 kg (38–44 lb)75 mL20 oz (~600 mL)

Lactulose is naturally sweet. Most children accept it well mixed with Gatorade.

⚠️ Lactulose may cause gas and bloating — this is normal. Contact the office if symptoms are severe.

📅 3 Days Before — Low-Residue Diet

AVOID OK to eat
Whole grains, nuts, seeds White rice, pasta, potatoes (no skin)
Raw fruits and vegetables Bananas, melons, cooked veggies
Corn, beans, popcorn Eggs, chicken, fish, yogurt, pudding

📅 1 Day Before — Low-Residue Through Lunch

After 2:00 PM — clear liquids only.

AVOID OK to eat / drink
RED or PURPLE drinks or foods Water, apple juice, white grape juice
Dairy (milk, yogurt, ice cream); juices with pulp Lemonade, clear soda, clear broth
Any solid food Popsicles, plain Jell-O, tea/coffee without milk

🥤 THE BIG PREP — afternoon / evening

Best to start right after school — don't delay too long, or your child may not finish before bedtime.

12:00 PM
Give Dulcolax tablets — 1 tablet (5 mg) — with a sip of water.
1:00 PM
Start the lactulose solution — the pre-mixed lactulose + Gatorade from the fridge (see the dose-by-weight table above for the amount).
Have your child drink 3 oz (~90 mL) every 30 minutes until finished.
💡 Tips for drinking the lactulose prep

Drink each cup fast (don't sip slowly — quick drinking helps the stomach empty and reduces nausea). Cold is easier — that's why we refrigerated it overnight. If your child can't keep up, pause 30 minutes and resume. If your child vomits, wait 30 minutes and restart at a slower rate.

⚠️ Rescue plan

If stools are not clear or pale yellow 4 hours after starting (or if no stools), give extra lactulose:

📅 Day of Procedure

⚠️ If the prep is not followed exactly, the colonoscopy may be delayed or canceled.

Helpful Resources

▶ Watch a video about the procedure Example only — follow this handout, not the video. 📨 Patient portal Message us — preferred contact method 🌐 GIKids.org General info on pediatric GI procedures

🍚 Low-Residue Diet — Sample Meals

Meal ideas for the low-residue (“white”) diet. Continue this diet for the 3 days before the procedure, through lunch the day before. After 2:00 PM the day before, switch to clear liquids only — no dairy.

Breakfast (morning)

  • Scrambled eggs
  • White toast with butter
  • Banana
  • Yogurt (no seeds or berries)
  • Apple juice

Lunch (~noon)

  • Plain chicken sandwich on white bread (no veggies)
  • Mac and cheese
  • White rice with chicken
  • Plain pasta
  • Applesauce
  • Vanilla pudding

After lunch (~2:00 PM onward)

  • Clear liquids only (see allowed drinks above)
  • No more dairy — milk, yogurt, ice cream, etc.
After the procedure & when to call

Call (317) 338-9450 if your child has any of the following after the procedure: