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Bowel Preps


What Option is Best for Your Patient?

Editor's Note: When hot topics were discussed with members of local endscopy suites, one issue was consistently debated--patient disobedience of bowel prep instructions. This lack of compliance can delay operations within the entire endoscopy suite and can be potentially harmful to the patient undergoing endoscopy procedures. The following article examines several bowel prep options on the market. The decision of pill vs. liquids is up to the physician, but endoscopy team members should be informed of the latest technology to help promote necessary compliance. This information is especially crucial since Medicare recently began covering colonoscopies, and a generation of Baby Boomers is just a few years from retirement.

Did You Know?

With increasing rates of inflammatory bowel disease (IBD), endoscopy procedures and bowel preps are becoming more important to the aging population.

* The prevalence of IBD will grow by .5% each year until 2008.

* 5% of IBD sufferers go undiagnosed in the US; up to 10% in Germany, and up to 15% of France.

* As many as 30% of IBD sufferers undergo surgery for ulcerative colitis.

* The total sales to treat IBD in 1998 in the US, France, Germany, Italy, Spain, Japan, and the United Kingdom was $516.8 million. This figure is expected to increase to $836 million by 2003 and $970.4 million in 2008.

Source: Crohn's & Colitis Foundation of America, Inc.

While most colonoscopy patients understand the need to clear the bowel completely prior to an endoscopy procedure, many balk at ingesting large quantities of unpleasant-tasting liquids. Wisconsin-based pharmaceutical firm Schwarz Pharma, Inc. manufactures a PEG lavage solution offered in fruit flavors that is designed to make the process of bowel cleansing more palatable. Colyte® PEG-3350 and Electrolytes for Oral Solution comes in packs of citrus berry, lemon lime, cherry, and pineapple flavors, as well as in unflavored powder.

The PEG lavage preparation is usually taken by the patient at home the night before the examination. Patients are instructed to dissolve the Colyte® solution in a sufficient quantity of water in order to produce a full liquid volume of 4 liters. Patients are advised to ingest 8 oz of the liquid solution every 10 minutes, drinking rapidly instead of sipping slowly. The patient should continue drinking the Colyte® until the watery stool is clear and free of solid matter.

Colyte® cleanses the bowel through the induction of diarrhea. The osmotic activity of Polyethylene Glycol 3350, in combination with the electrolyte concentration, results in virtually no net absorption or excretion of ions or water. Accordingly, large volumes may be administered without significant changes in fluid and electrolyte balance. Each 4-liter bottle of Colyte® contains 240g of polyethylene glycol 3350, 5.84g of sodium chloride, 2.98g of potassium chloride, 6.72g of sodium bicarbonate, and 22.72g of sodium sulfate (anhydrous).

Colyte® is contraindicated in patients with toxic colitis, gastrointestinal obstruction, gastric retention, bowel perforation, or toxic megacolon. According to Schwarz Pharma, Colyte's® flavor packs should be used with caution with individuals suffering from severe ulcerative colitis.

Adverse reactions to Colyte® have included nausea, abdominal fullness, and bloating in up to half of all patients ingesting the solution, with abdominal cramps, vomiting, and anal irritation occurring less frequently. Isolated cases of dermatitis, rhinorrhea, and urticaria resulting from allergic reactions have been reported. While the safety and efficacy of use in pediatric patients has not been established, isolated reports of serious adverse reactions in patients over the age of 60 have been noted. Such adverse events have included upper GI bleeding from Mallory-Weiss Tear, esophageal perforation, and sudden dyspnea with pulmonary edema. According to the package insert, it is not known if Colyte® has the potential to affect reproductive capacity of both sexes or harm the fetus when administered to a pregnant woman.

Schwarz has been marketing Colyte® for bowel cleansing or barium enema X-ray examination since 1995.

When GoLYTELY® products hit the market in 1984, they had few competitors. They quickly became well known within endoscopy suites and helped create the bowel prep industry; however, with their successful product came a few complaints.

Their product, GoLYTELY,® was effective, but patients were complaining that it was too salty. The powder is mixed with 4 liters of water and taken in one dose a day before the procedure. Researchers at Braintree decided adding flavoring could help by masking the salty taste. Soon after, Golytely® in a pineapple flavor was introduced and was soon financially successful. But there were still patients who needed something with less salt.

In a 1990 article written by John S. Fordtran, Carol A. Santa Ana, and Mark B. Cleveland from the Department of Internal Medicine at Baylor University Medical Center in Dallas, Texas, the process of developing a new product with less salt is discussed. Their article, "A Low-Sodium Solution for Gastrointestinal Lavage," covers the differences in Braintree's formula for Golytely® and a new product with 52% less salt, Nulytely.®

One of the problems with bowel prep products before 1990 was they required the patient to ingest isotonic saline. A large group of these patients were unable to process the solution. They could not excrete large salt and water loads. Golytely® was designed to decrease salt and water absorption. The new Braintree product, Nulytely,® was designed similarly to the previous product, but the solution was created without sodium sulfate. Sulfate is poorly absorbed. Also, the new formulation included increased amounts of polyethylene glycol (PEG).

This new product was developed with two features in mind: to be associated with negligible net absorption, secretion of water, and electrolytes, and to have a lower sodium concentration that the previous product to reduce the salty taste. The authors found these objectives were reached by removing the sodium sulfate and increasing the concentration of PEG within the original product to create Nulytely.®

In 1991, Braintree placed Nulytely® on the market. Ten years later, the product is available in orange, lemon-lime, and cherry flavors. Nulytely® is the only bowel prep on the market offered with an orange flavor.

There are some contraindications surrounding these bowel preps patients should be aware of. Those with gastrointestinal obstruction, gastric retention, bowel perforation, toxic colitis, toxic megacolon, or ileus should not use this product.

The primary issues regarding bowel preparation today are patient acceptance and compliance. Questions of whether a product is best provided in liquid or pill form are subordinate to the acceptability of the laxation program as a whole. Regardless of the method of ingestion, both PEG and sodium phosphate preps challenge patient compliance by being physically demanding, high in sodium content, and difficult or complicated to administer. This all contributes to the commonly held perception that prepping is the most disagreeable aspect of the colonoscopy procedure.

Bowel preparation using E-Z-EM's LoSo Prep™ and NutraPrep™ products represents a significant departure from conventional prepping with either PEG or sodium phosphate laxative (in either liquid or table form). Both of these new products emphasize patient comfort, compliance, and ease of administration.

LoSo Prep™

LoSo Prep™ is a complete bowel cleansing system that eliminates the major sources of patient dissatisfaction common to other preps. Each kit includes a 1.2 oz packet of effervescent magnesium citrate that produces approximately 8 oz of laxative, for the patient to consume on the evening prior to his or her procedure. Bowel evacuation with LoSo Prep™ is thorough, comparatively gentle, and offers significant advantages in several areas important to patient acceptance.

Low Liquid Volume

Consuming large volumes of fluid during a short period of time is a major complaint associated with the prepping process. Except for periodically taking in liquids to maintain proper hydration, LoSo Prep™ requires patients to drink one 8 oz portion of magnesium citrate. Contrast this small amount of liquid with the 3 to 4 liters of PEG laxatives that must be consumed for thorough cleansing.

Low Sodium Content

Sodium content is an issue for many patients, and particularly those who are elderly. At less than 35 mg, LoSo Prep™ is the only prep that meets the FDA criteria for very low sodium content. In comparison, a sodium phosphate laxative--either in liquid or tablet form--typically requires the patient to ingest 5,000-10,000 mg of sodium. PEG laxatives may include anywhere from 6,000 mg of sodium to nearly 14,000 mg, depending on the particular formulation. Its low sodium content means that LoSo Prep™ is suitable for all patients, even when hypertension or heart disease is a consideration.

Pleasant Taste

LoSo Prep™ has a naturally pleasing citrus flavor. It avoids the strong chemical or saline tastes that make PEG and sodium phosphate preparations difficult to ingest or keep down. Unlike these other preps, there is no need to disguise LoSo Prep's™ taste by chilling and diluting the preparations, or through the addition of supplemental flavorings.

Easy Preparation and Administration

Preparing LoSo Prep™ magnesium citrate requires the patient or healthcare worker (HCW) to empty the contents of a 1.2 oz packet of powder into an 8 oz glass of pater. Constrast this to reconstituting 3 to 4 liters of PEG laxative and drinking it in 8 oz doses, or to mixing small amounts of liquid sodium phosphate with diluting beverages and consuming them in sequence. In the past, sodium phosphate preps have been vulnerable to inadvertent overdosing, resulting in serious medical consequences.

The compliance-relating factors indicated are summarized in table 1.

Contributor Robert Mattson, BS, MA, is the executive vice president of Sanna Mattson MacLeod, Inc. in Smithtown, NY.

Table 1:
Comparison of Prepping Regimens with Regard to Factors Affecting Compliance

  Liquid Volume Sodium Content Taste Ease of Colon Prep Administration
LoSoPrep™ 8 oz laxative, 8 oz of water 35mg Requires no added flavorings Consume one 8 oz glass of laxative; 4 bisacodyl tablets with 8 oz of water; suppository with bisacodyl tablets
PEG Laxatives 3 to 4 liters 2,500 mg to 10,000 mg Requires flavoring to cover taste Reconstitute and consume in 8 oz glasses at 15-minute intervals
Sodium Phosphate (Liquid) 90-ml dose plus diluent 5,000-14,000 mg Dilution recommended to cover taste Dilute and consume at 20-minute intervals
Sodium Phosphate Not applicable 6,000 mg (approx.) Requires no added flavorings Consume 40 pills in three-pill doses, with water, at 15 minute intervals

From 1985 to 1997, the mortality rate from colorectal cancer declined annually by about 1.8%; yet it is still estimated that about 5.6% of Americans will develop the disease. When colorectal cancer is diagnosed early while still localized, the five-year survival rate is 90%.1 The same procedures used to diagnose colorectal cancer at early, curable stages can also identify and remove precancerous polyps. Therefore, colonoscopy may actually help prevent colorectal cancer.1

Healthcare workers (HCWs) know that the most dreaded--and possibly the most misunderstood--part of the entire colonoscopy procedure is the bowel preparation. As well, the quality of the bowel prep also is a primary factor in the efficacy of colonoscopy as a diagnostic and preventive tool. The procedure can only be effective to the extent that the prep was effective.2

The Health Belief Model

The mere fact that a patient has received information about a treatment plan doesn't guarantee compliance, and nurses in practice have observed that the same is true of patients preparing for diagnostic procedures. Much research has been conducted in an effort to identify key predictive factors influencing patient compliance. A theoretical construct known as the Health Belief Model explains the primary factors in compliance.3

According to the Health Belief Model, patients are more likely to comply with treatment plans when they believe that the prescribed actions are less threatening than the disease itself. Conversely, reasons for non-compliance may include the following:

* Fear of medication side effects (a fear that the treatment may be worse than the disease)

* Failure to understand directions about the plan (such as difficulty distinguishing "clear liquids")

* Impaired manual dexterity (inability to open containers of medication) or

* Sensory deficit (inability to read or understand written instructions).3

By understanding what is required of a bowel prep for effective colonoscopy and applying the theories behind the Health Belief Model, HCWs can infer the characteristics of an "ideal" bowel prep. While no prep is perfect, comparing any bowel prep to these criteria will help you evaluate its usefulness for a particular patient.

The "ideal" bowel prep

There are four key components to the ideal bowel prep: it is easy to use, it is convenient, it is well tolerated, and it is effective.5 The perfect prep reliably empties the colon of all formed and most liquid matter, has no effect on the gross or microscopic appearance of the colon, requires a relatively short time for ingestion and evacuation, results in minimal patient discomfort, and results in no significant shifts in fluid or electrolyte levels.5

Among several bowel preparation methods currently available in the market is small volume Fleet® Phospho-soda.® This bowel prep offers a convenient dosing regimen known as the "Dilution Solution." For each dose, patients drink three 8 oz glasses of clear fluid over the duration of 20-30 minutes, each with one tablespoon of Fleet® Phospho-soda® added.

For improved taste, patients can mix one tablespoon of Fleet® Phospho-soda® with 8 fluid oz of a chilled clear beverage of choice, then repeat twice more within 20 minutes.

As for its effectiveness as a bowel prep, a recent survey revealed that 46% of colo-rectal surgeons reported they prefer Fleet® Phospho-soda® for bowel preparation. (PEG users accounted for 32%, with another 15% selectively alternating between Phospho-soda® and PEG).8

Fleet® Phospho-soda® is a sodium phosphate-based prep and should not be used in patients with congenital megacolon, bowel obstructions, ascites, or congestive heart failure. It should be used with caution in patients with impaired renal function, pre-existing electrolyte imbalances, or with debilitated patients, as hypocalcemia, hypokalemia, hyperphosphatemia, hypernatremia, and acidosis may occur. Calcium and phosphorus levels of patients taking Fleet® Phospho-soda® should be monitored. Serious side effects may occur from excess dosage.9

Contributor Sherrie Scott, RN, BSN, is medical affairs coordinator for Virginia-based C.B. Fleet Co., Inc.


1. Smith, RA, et al. American Cancer Society guidelines for the early detection of cancer: update of early detection guidelines for prostate, colorectal, and endometrial cancers. A Cancer Journal for Clinicians 2001;51:38-75.

2. Gulanick, M and Kiopp, A. Gastrointestinal and digestive care plans - noncompliance. Nursing Care Plans/Nursing Diagnosis and Intervention (4th ed.) 1998;135-138.

3. Brown, KM. Health Belief Model. Univ of South Florida 1998

4. Wexner, S. Optimizing the outcome of mechanical bowel preparation. Presentation at SAGES conference 2001

5. Raymond, P. Ins & outs of colonoscopy preps. Presentation at SGNA conference 2001.

6. Hsu, C and Imperiale, T. Meta-analysis and cost comparison of polyethylene glycol lavage versus sodium phosphate for colonoscopy preparation. Gastrointest Endosc 1998;48:276-82.

7. Oliveira, L, et al. Mechanical bowel preparation for elective colorectal surgery: a prospective, randomized, surgeon-blinded trial comparing sodium phosphate and polyethylene glycol based oral lavage solutions. Dis Colon Rectum 1997;40:585-591.

8. Wexner, S. Unpublished personal data presented at SAGES conference 2001.

9. Physicians Desk Reference,

The US Food and Drug Administration (FDA) approved the first oral tablet bowel prep for colonoscopy in September, 2000. By January 4, 2001, InKine Pharmaceutical Company had shipped their first commercial orders of this new drug--Visicol™ Tablets.

According to officials at InKine, Visicol™ was developed to help patients who complained about the taste, viscosity, and volume of liquid bowel preps. To answer these complaints, InKine formulated an oral tablet of sodium phosphate salts, and then performed clinical trials to demonstrate that the tablets are safe and effective in cleansing the colon.

The 40-tablet process, taken as three tablets every 15 minutes for a total of 20 tablets the evening prior to colonoscopy, and then repeated 3 to 5 hours before colonoscopy, prepares patients for their upcoming procedure. Another option available to patients is a 4 liter polyethylene glycol (PEG) liquid bowel prep, which has to be taken the day before the procedure. Both of these preparations are available by prescription only. In clinical trials, Visicol™ demonstrated similar colon cleansing, with better patient acceptance and tolerance, compared to the 4 liter PEG solution.

Each Visicol™ tablet contains 1.102 grams sodium phosphate monobasic monohydrate USP, and .0398 grams sodium phosphate dibasic anhydrous USP. Each three tablet dose should be taken with an 8 oz glass of water, to help patients remain well hydrated. The two 20-tablet dosing regimens provide an equivalent amount of sodium phosphate (60 grams) as that found in the OTC liquid sodium phosphate purgative.

Visicol™ tablets induce diarrhea within 1 to 3 hours in most patients, but may take longer in some patients. The tablets work by causing large amounts of water to be drawn into the bowel through osmotic action, purging, and cleansing the colon.

Two identical Phase III trials, with more than 400 patients in each, compared Visicol™ tablets to the leading PEG solution. The results are to be published in Gastrointestinal Endoscopy. In these trials, overall colon cleansing was judged either Good or Excellent in 84% of patients taking the tablets, compared to 76% of patients taking the PEG solution (p=ns). Less than 1% of the 420 patients who took Visicol™ reported problems taking the tablets due to taste, and more than 90% said they would use the tablets again if they needed another colonoscopy. Significantly fewer patients taking Visicol™ reported nausea, vomiting, or bloating compared to those taking the PEG solution. From these studies, researchers concluded the tablets were equivalent in efficacy to the leading PEG solution for overall colon cleansing, but they were better accepted and tolerated by patients.

Results from a Phase IV multi-center trial will be presented at the American College of Gastroenterology (ACG) in Las Vegas, Nev, October 21-24, 2001. The trial examines Visicol's™ effectiveness using fewer tablets for the second dose and less liquid volume.

In this study patients took the first 20 tablets as four tablets every 15 minutes, completing the dose in a one-hour time period the night before their procedure. The next morning, they took either eight tablets or 12 tablets, also as four tablets every 15 minutes. Thus, the second dose could be completed in 15 or 30 minutes. This new dosing regimen would reduce the time needed to complete taking the pills. Researchers decided to experiment with the time frame and number of tablets to make the dosing regimen even easier for patients.

There are some contraindications surrounding use of this bowel prep. Visicol™ causes serum sodium and phosphate to rise, and these electrolytes are cleared by the kidneys. It should be used with caution in patients who have impaired renal function or any problem with electrolyte disturbances. In clinical trials Visicol™ was not used in patients whose creatinine was above 2.0 mg/dL. Patients with congestive heart failure, ascites, unstable angina pectoris, or some GI abnormalities should not use this product.

In clinical trials the following side effects were most common and were seen in more than 3% of patients: nausea, vomiting, abdominal bloating, and, abdominal pain. Dizziness and headache were seen in less than 3% of patients, and were seen with both Visicol™ and the PEG solution.

In February, InKine announced it was entering into an agreement with Proctor & Gamble to promote Visicol.™ P&G gastrointestinal sales force contacts more than 90% of gastroenterologists in the US. The two companies will work together for 18 months to give gastroenterologists and colorectal surgeons more information about the new bowel prep option.

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