Bowel preparation for colonoscopy

How to take OnePrep 1.38 (1.38 L liquid)

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Exam: (date) :

This is Gwanak Soo Internal Medicine Clinic. For patients having a colonoscopy, here is how to take the bowel preparation medicine OnePrep 1.38.

Taking it as instructed cleans the bowel so the exam goes well. If the bowel is not fully emptied, polyps are hard to find and you may need to have the exam again.

Your timeline

  1. From 3 days before Avoid the foods below
  2. Day before Light breakfast and lunch only · no food after 2 pm · water or sports drinks 0.5–1 L
  3. Exam day, 4 hours before the exam 1st and 2nd dose — 9 am exam: 5 am · 2 pm exam: 10 am
  4. 2 hours before the exam Stop drinking water
  5. Exam day Colonoscopy — no food on the day of the exam

Take OnePrep 1.38 on the day of the exam, 4 hours before the exam. For a 9 am exam that is 5 am; for a 2 pm exam it is 10 am. Please follow the exact time written on the instruction sheet the clinic gives you.

Food from 3 days before

Avoid

  • Watermelon
  • Korean melon
  • Strawberries
  • Grapes
  • Kiwi
  • Tangerines
  • Multigrain and brown rice
  • Sesame and sesame porridge
  • Corn
  • Nuts
  • Beans and bean sprouts
  • Kimchi and kkakdugi
  • Namul and spinach
  • Cabbage and salad
  • Green onions
  • Mushrooms
  • Chili pepper seeds
  • Gim (dried laver)
  • Miyeok and kelp

OK to eat

  • White rice
  • Plain rice porridge
  • Eggs
  • Tofu
  • Muk (jelly)
  • Fish
  • Lean chicken meat
  • Clear broth without solids
  • White bread
  • Castella (sponge cake)
  • Apples (no skin or seeds)
  • Pears (no skin or seeds)
  • Bananas
  • Potatoes
  • Water
  • Sports drinks
  • Clear juice

Foods to avoid from 3 days before the exam: fruits with seeds such as watermelon, Korean melon, strawberries, grapes, kiwi and tangerines; multigrain rice and brown rice; sesame and sesame porridge; corn; and nuts.

Also avoid beans and bean sprouts, kimchi and kkakdugi (radish kimchi), namul (seasoned vegetables) and spinach, cabbage and salad, green onions, mushrooms, chili pepper seeds, gim (dried laver), miyeok (seaweed) and kelp.

Foods you may eat: white rice and plain rice porridge, eggs, tofu, muk (jelly), fish, lean chicken meat, clear broth without solids, white bread and castella (sponge cake).

You may also eat apples and pears with the skin and seeds removed, bananas, potatoes, and drink water, sports drinks or clear juice.

On the day before the exam, eat only a light breakfast and lunch of plain rice porridge with soy sauce, broth without solids, or castella. Do not eat after 2 pm; after that, drink plenty of water or sports drinks, about 0.5–1 L. Do not eat on the day of the exam.

How to take it

You need one box of OnePrep 1.38 and bottled water. The box contains 2 sachets of powder A, 2 sachets of powder B, a 230 mL cup and an anti-foaming agent.

  1. 1

    Mix

    How to mix: just before drinking, put 1 sachet of powder A and 1 sachet of powder B into the cup, fill with water up to the 230 mL mark, and stir well to dissolve.

  2. 2

    1st dose

    1st dose: drink the mixed medicine one sip at a time over 10 minutes. Then drink 2 cups of water (460 mL) one sip at a time over 20 minutes. Go slowly, 2–3 sips a minute; using a straw is even better.

    ☐ Day before  ☐ Exam day  ·  ☐ AM  ☐ PM  ·   :

  3. 3

    2nd dose

    The 2nd dose is the same as the 1st: make one more cup with the remaining powders A and B, drink it over 10 minutes, then drink 2 cups of water over 20 minutes.

    ☐ Day before  ☐ Exam day  ·  ☐ AM  ☐ PM  ·   :

  4. 4

    Anti-foaming agent

    After you have finished OnePrep, squeeze out and take the anti-foaming agent at the very end.

Water

You drink a lot of water to prevent dehydration.

Drink water only until 2 hours before the exam; after that, do not drink even water.

Are you ready?

Stool colour changes from dark brown to brown, dark orange, light orange and finally clear yellow
  1. Dark brown
  2. Brown
  3. Dark orange
  4. Light orangeAlmost ready
  5. Clear yellowReady

When your last diarrhea comes out clear like urine, you are ready. Even if your stool is already clear, finish all of the medicine.

If this happens

If you feel queasy or about to vomit, rest for 10–20 minutes and then continue. Taking deep breaths helps.

If you feel very dizzy, sit or lie down on the floor right away. If you vomit or have severe belly pain, stop, and continue after you feel better.

While taking it, walking around or rubbing your belly empties the bowel better than lying down.

If you vomit a lot or feel very dizzy, stop taking it and call the clinic.

Your usual medicines

Take blood pressure or heart medicine early in the morning on the day of the exam with a sip of water. Diabetes medicine and insulin are adjusted differently depending on the type and the exam time. Tell us the name and dose of your medicines when you book, and do as instructed. Do not stop all of them on your own.

If you take a blood thinner such as aspirin, clopidogrel or warfarin, be sure to talk to the doctor who prescribed it before the exam.

Gwanak Soo Internal Medicine ClinicIf you have any questions, call Gwanak Soo Internal Medicine Clinic at +82-2-871-1936.2F, 1810 Nambusunhwan-ro, Gwanak-gu, Seoul · Seoul Nat’l Univ. Station Exit 4
Scan to open this guide on your phonewww.gwsooclinic.com/en/prep/oneprep

Video (Korean): watch on our Korean page · Other bowel preparations: Halfprep (2 L liquid) · Orafang (tablets) · Back to the clinic page