How To Prep for Colonoscopy w/ Osmoprep - Osmoprep Prep Instructions

Colonoscopy with Osmoprep

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If you are 55 years of age or older, have kidney problems or congestive heart failure, you should take a different preparation than Osmoprep.


There are many things a person would rather do than undergo a bowel prep for a colonoscopy, but your efforts at cleansing your colon are essential for an accurate procedure. These instructions are designed to maximize the ease, safety and success of your preparation. Please read these instructions carefully at least one week prior to your exam. Obtain the Osmoprep from the pharmacist (Note: this requires a prescription).

Medication and Diet Instructions:

Seven days before the procedure:

Stop taking aspirin (and aspirin-containing products) and Plavix (clopidogel). Acetaminophen (Tylenol) can be continued or substituted as a pain-reliever for aspirin.

Three days before the procedure:

Stop taking Coumadin (warfarin). If you have an artificial heart valve, you need to talk to your primary care physician or cardiologist about using an alternative anticoagulant.

Stop taking anti-inflammatory medicines such as Aleve, Motrin, Advil, Ibuprofen and Naproxyn.

Avoid eating nuts, seeds, popcorn, grapes, green peas, beans and tomatoes. Fibers from these foods can clog the colonoscope.

On the day before the procedure:

You may have a light, low fiber breakfast early in the morning (e.g. eggs, white toast – no butter). Do not eat vegetables, fruits, nuts, butter, milk, cheese, meat, or whole grain cereals. You must drink plenty of fluids throughout the day – it is recommended that you drink a minimum of 32 ounces of clear liquids spread out over the day before you start your prep. After breakfast, you will be on a clear liquid diet. Avoid juices with pulp such as orange or grapefruit juice. No dairy products, cream or soy. Coffee and tea are O.K. Examples of clear liquids include broth or bouillon, Jell-O, clear juices (white grape or apple), sports drinks such as Gatorade or PowerAde, sodas such as Sprite, 7-Up, or gingerale, lemonade, Popsicles, coffee or tea and of course, water. Avoid red or purple colored liquids. You may use sugar, honey or lemon.

You may notice that our instructions vary from the package insert. Our instructions are based on the latest information to maximize ease, convenience and success of the prep. Osmoprep is taken in two parts, at least 5 hours apart. Take each dose with 8 ounces of any clear liquid. Remember, stay close to the bathroom facilities and warn family members that the room belongs to you!!! It is also worthwhile to get a supply of aloe wet wipes and Desitin ointment to ward off a sore bottom.

Step 1:

The night prior to your exam, beginning at 5-8 pm, take 4 tablets with 8 ounces of any clear liquid every 15 minutes for a total of 5 doses (total 20 tablets). You may drink as much clear liquid as you wish before going to bed.


Step 2:

On the day of the exam, starting 4-5 hours before your appointment time, take 4 tablets with 8 ounces of any clear liquid every 15 minutes for a total of 3 doses (total 12 tablets). You may drink as much clear liquid as you wish up to 2 hours prior to your appointment


Day of the procedure:

  • Do not eat or drink anything for at least 2 hours prior to your appointment.
  • You must be accompanied by a friend or relative to drive or assist you home. You will not be allowed to drive for 12 hours after the procedure.
  • You should take your regular medications with sips of water unless you are instructed otherwise.

Special Instructions:

  • If you are a diabetic taking insulin, hold the morning dose of insulin the day of the procedure.
  • If you have an artificial heart valve, or have a previous history of endocarditis, or other specific indication, call us.
  • Be sure to remember any allergies to medications and to Latex, or conditions that would make you sensitive to sedation such as sleep apnea syndrome

Commonly asked Questions:

How do I know if my prep is adequate?

The stool should be watery in consistency. It does not have to be clear in color like water since digestive juices will continue to tint the stool yellow and small flecks of debris are not a problem as long as the stool is not muddy or thick. If there is any question, you can self administer a fleet enema prior to leaving home for the procedure.

What side effects may I expect?

Since the prep works by flooding the intestinal tract with fluid, abdominal bloating and cramping may occur, as well as some nausea and vomiting. This is usually temporary, and as the diarrhea develops, symptoms will gradually improve. Weakness can also occur, especially if you have not taken enough fluid with the prep, and can be remedied by increasing fluid intake (especially with the sports drinks such as Gatorade or PowerAde).

Will the prep interfere with my other medications?

Medications taken at least an hour before beginning the prep should be adequately absorbed, but thereafter, they are likely to be washed away by the prep.

What if I have other questions?

Call our office to address any other concerns not answered here.

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