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Pediatric Gastroenterology
(317) 338-9450
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Colonoscopy Bowel Prep

15–20 kg[33–45 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.

⚠️ 💊 Medications

Prepare a list of medications.
Stop iron, anti-diarrhea medicine 7 days before.
You can verify what medications 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.

Medications and Supplies needed

Pick up any prescription as soon as possible after scheduling. Buy all other supplies at least 5 days before the procedure. Check the active ingredient on the label.

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

📅 1 Day Before — Diet & Bowel Prep

Two parts today: the diet below, then THE BIG PREP — the bowel-prep medicines — in the afternoon and evening.

The Diet — breakfast & lunch: Low-Residue (“White”) foods

Low-residue foods only — the table pairs meals that work with the ones to skip. Nothing with whole grains, red meat, nuts, seeds, popcorn or beans, and nothing fried or greasy. No vegetables that day except plain potato without the skin; fruit only if it is soft and peeled.

✅ OK to eat (breakfast & lunch) ❌ Instead of
Scrambled eggs + white toast with butterWhole-wheat toast, oatmeal with nuts or berries
Pancakes or waffles, plain or with syrupWhole-grain waffles, berries, granola topping
Grilled chicken sandwich on white bread, no lettuce or tomatoBurger and fries, pizza, anything fried
Mac & cheese + applesauceSalad, raw veggies, corn
White rice + baked chicken or fish + bananaBrown rice, beans, steak or ground beef
Snacks before 2 PM: plain yogurt, pudding, Jell-O, white crackers, pretzels, melonGranola bars, popcorn, trail mix, fruit with the skin on

After 2:00 PM — Clear Liquids Only

No more solid food. No dairy — no milk, yogurt, or ice cream.

✅ OK to drink ❌ Skip that day
Water, apple juice, white grape juiceRED or PURPLE drinks or foods
Lemonade, clear soda, clear brothDairy (milk, yogurt, ice cream); juices with pulp
Popsicles, plain Jell-O, tea/coffee without milkAny solid food

🥤 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). 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:

  • Evening: give 30 mL more lactulose in 8 oz of Gatorade.
  • Morning of procedure: give 15 mL more lactulose in 4 oz of Gatorade, at least 3 hours before the procedure.

📅 Day of Procedure

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

Helpful Resources

After the procedure & when to call
  • Your child will wake up in the recovery area. Some grogginess and gas/cramping/bloating are normal for several hours.
  • A small amount of blood with the first stool after a colonoscopy can be normal, especially if biopsies were taken.
  • An adult must stay with your child for 24 hours after anesthesia.
  • Start with clear liquids, then advance to a regular diet as tolerated.
  • No school, daycare, or sports for the rest of the day. Most children are back to normal activity the next day.
  • The doctor will discuss what was seen before you go home. Biopsy results take about 1–2 weeks; we'll send the results to the portal and discuss over the phone or at the next appointment.

A sore throat, mild cramping and extra gas are common for about a day, and streaks of blood in the first stool or in vomit can be normal after biopsies. Call (317) 338-9450 if your child has:

  • A temperature over 101°F (38.3°C)
  • More than about a tablespoon of blood, in stool or in vomit, or stool that is black
  • Severe or worsening abdominal pain — call us, and we will tell you whether to be seen
  • Severe or persistent sore throat, drooling, or trouble swallowing
  • Difficulty breathing or chest pain — this is an emergency, call 911

After hours, the same number reaches the provider on call.