Myth of the Month

Colonoscopy prep suggestions for those who hate it


A 61-year-old man is seen for a primary care visit. He has a history of colonic polyps (tubular adenoma) on two previous colonoscopies (at age 50 and 55). He has been on an appropriate 5-year schedule, but is overdue for his colonoscopy. He did not follow up with messages from his gastroenterologist for scheduling his colonoscopy last year. He explains he really hates the whole preparation for colonoscopy, but does realize he needs to follow up, and is willing to do so now. What do you recommend for colonoscopy prep?

Dr. Douglas S. Paauw, University of Washington, Seattle

Dr. Douglas S. Paauw

A) Diet as usual until 5 p.m. day before, then clear liquid diet. Start GoLYTELY (1 gallon) night before procedure.

B) Low-fiber diet X2 days, clear liquid diet day before procedure, GoLYTELY (1 gallon) night before procedure.

C) Low residue diet X3 days, SUPREP the night before the procedure.

D) Low residue diet X2 days, followed by clear liquid diet the day before the procedure, SUPREP the night before the procedure.

It is common for patients to be reluctant to follow recommendations for colonoscopy due to dreading the prep. I would recommend choice C here, as the least difficult bowel preparation for colonoscopy.

Gastroenterologists are usually the ones to recommend the bowel prep that they want their patients to follow. When patients avoid needed colonoscopies because they hate the prep they are advised to take, I think it is good for primary care professionals to step in and discuss evidence-based alternatives.

Major diet change for several days before colonoscopy is difficult for many patients. Standard advice is that patients eat only low-fiber foods starting 3 days before the procedure. Patients are advised to switch to a completely clear liquid diet 1-2 days before the colonoscopy.

Are there more tolerable diets to offer patients?

Soweid and colleagues randomized 200 patients to a low residue diet for the three meals the day before colonoscopy vs. clear liquid diet.1 The low residue diet allowed patients to eat meat, eggs, cheese, bread, rice, and ice cream. Not surprisingly, patients tolerated the low residue diet better with statistically significantly less nausea, vomiting, weakness, headache, sleep difficulties, and hunger. The patients in the low residue diet group also had better bowel prep than did those in the clear liquid diet group (81% vs. 52%, P less than 0.001).1

In a recent meta- analysis, low residue diets were comparable to clear liquid diets in regard to adequacy of bowel prep and for detection of polyps.2 Patients who followed low residue diets had statistically significantly less headaches, nausea, vomiting, and hunger. Very importantly, patients who followed low residue diets showed an increased willingness to repeat it, compared with those who followed a clear liquid diet (P less than .005; odds ratio, 2.23; 95% confidence interval, 1.28-3.89).2

What alternatives to GoLYTELY exist?

Another part of the bowel prep that patients struggle with is drinking a gallon of GoLYTELY (polyethylene glycol/electrolytes). Drinking that amount of this nasty stuff is never welcome.


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