Aman Singh, MD, Gastroenterolgy for Women logo for print
11525 Olde Cabin Rd, St. Louis, MO 63141
Phone: (314) 997-0554

Aman Singh, MD Gastroenterologist

Preparation using OsmoPrep

Colonoscopy Preparation using OsmoPrep 2 Day PM/AM Split Dosing Regimen

The colon preparation is the most important step leading to the successful completion of a colonoscopy. We know it is inconvenient, but a clean colon will lead to an efficiently and safely performed colonoscopy that will lead to good gastrointestinal health.

Seven Days Before the Procedure

Medication restriction

  1. Diabetics taking insulin will need dose adjustment the day before the exam. Please ask for advice from the physician that prescribes your insulin. For diabetics taking only diabetic pills simply stop the pills the day before the procedure (see below).
  2. Blood thinners including Coumadin, aspirin, and Plavix type medicines. These can increase the risk of bleeding during endoscopic procedures to a varying degree. We recommend stopping Coumadin three days before the procedure, if possible. Please ask for advice from the physician that prescribes your Coumadin. If aspirin is used for preventative reasons and not for active cardiac or stroke prevention then it should be stopped for 7 days before the procedure. Discuss the use of other blood thinners, such as Plavix, with the prescribing physician.

Items to Purchase

  1. Fill the prescription for OsmoPrep (check for a rebate coupon in the office).
  2. Fill the prescription for Tigan (anti-nausea) drug. 
  3. Any over-the-counter hemorrhoid ointment for anal discomfort (if needed).

Threee Days Before the Procedure

No seeds, nuts, popcorn or peels from fruits and vegetables

One Day Before the Procedure

  1. For breakfast and lunch you may choose one of the following:2 eggs or 1 yogurt (any kind), or 1 ensure then clear liquids only for the remainder of the day.
  2. You cannot have milk or orange juice for the entire day.
  3. Drink as much as you can to prevent dehydration. You may have bouillon, broth, black coffee (sugar is okay), tea, juice (apple, grape, cranberry), Gatorade, lemonade, soda, water, Popsicles and Jell-O (any flavor or color). Red Jell-O and red Gatorade may turn your bowel movements red, but are fine, but should be limited.
  4. You may have clear candy (such as Lifesavers, Jolly Ranchers).
  5. Do not take oral diabetic pills.

Timing of Preparation

The Evening Before the Procedure

This is a preparation that requires you to take pills with liquid in two sessions. You must drink the entire OsmoPrep as prescribed to ensure your colon will be cleaned out. A poor prep can mean missed lesions (flat polyps) and cancellation and rescheduling of your procedure.

Starting at 6:00 p.m.
  1. Take 4 OsmoPrep tablets every 15 minutes with at least 8oz of clear liquids (or any liquid listed on the front page) until you have taken 20 tablets (five doses). It is very important that you drink a full 8oz of clear liquid with each dose.
  2. Do not exceed 20 tablets.
  3. If you become nauseated, stop drinking the OsmoPrep. Take one of the Tigan capsules. Resume drinking the OsmoPrep after 30 minutes, or when the nausea passes. If you do not use the Tigan, then it can be kept in case you have nausea in the future.

The Morning of the Procedure

Beginning 4-6 hours prior to your scheduled procedure time, take 4 OsmoPrep tablets every 15 minutes with 8oz of clear liquid (or any liquid listed on the front page) until you have taken 12 tablets for three doses. It is very important that you drink a full 8oz of clear liquid with each dose. Do not exceed 12 tablets.

  1. You should take any necessary medications you normally use on the morning of the procedure with sips of water. Take nothing by mouth, including water, after completing the last OsmoPrep dose.
  2. Take your regular medications on the morning of the procedure with sips of water.
  3. Arrive at your scheduled appointment time.
  4. Bring a list of your medications, insurance cards and photo ID.
  5. After the procedure you must have a responsible adult drive you home. It is best if your driver waits for you at the endoscopy center. You may be dropped off and picked up by a responsible person approximately one and a half hours later. Taking a cab home is not an option.
  6. You may not drive or work until the next day.

*Patients should NOT use OsmoPrep for their colonoscopy preparation if they have one or more of the following: congestive heart failure, ascites, angina (chest pain from the heart), renal insufficiency, less than 1 bowel movement per week, stomach doesn’t empty well, allergy to sodium phosphate salts, ileus or acute obstruction, gastric retention, bowel perforation, acute colitis, toxic megacolon, gastric bypass or stapling surgery, hypomotility syndrome.

Important Information About Sedation

Sedatives used for endoscopy include Propofol. These medications provide amnesia and pain relief. You are breathing on your own. It is not considered general anesthesia. The only reasons not to receive Propofol are pregnancy, egg allergy and soy allergy.

Questions or Problems

  1. Daytime phone number is (314) 997-0554.
  2. After hours number is (314) 388-6578.
  3. Internet website address is

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