Published online Mar 21, 2014. doi: 10.3748/wjg.v20.i11.2741
Revised: October 18, 2013
Accepted: November 3, 2013
Published online: March 21, 2014
Adequate bowel preparation is important for successful colonoscopic examination. Several effective colonic cleansing agents are available and routinely prescribed, but each carries its own limitations and benefits from particular dosing regimens. The most frequently prescribed colonic cleansing agent, the polyethylene glycol (PEG) cathartic solution, suffers from low patient compliance in general, due to its unpalatable taste and smell coupled with the large ingested volumes required. However, PEG is preferred over other cathartics for use in individuals of advanced age, sufferers of chronic kidney disease, heart failure and inflammatory bowel disease, and women who are pregnant or lactating. The laxative agents sodium phosphate (NaP) and sodium picosulfate plus magnesium citrate have been applied and have improved patient compliance and tolerance. NaP, however, should be avoided in individuals with impaired renal function or plasma clearance, such as those with chronic kidney disease, who are taking drugs that affect renal function, or who suffer from heart failure. Other special conditions that may affect an individual’s tolerance of the cathartic agent or ability to complete the administration routine include stroke, severe constipation, hematochezia, suspicious lower gastrointestinal bleeding, and mental disorders such as dementia. All ingestible bowel preparation solutions can be instilled into the stomach and duodenum through nasogastric tube or esophagogastroduodenoscope with the aid of a water irrigation pump for patients with difficulties swallowing or ingesting the large volumes of fluid required. In addition, dietary regimens based on clear liquids and low-residue foods for 1-4 d prior to the colonoscopy may be supplemental bowel preparation strategies. Achieving an effective and safe cleansing of the bowel is important for successful colonoscopy in all patients, so full knowledge of the individual’s condition and capabilities is necessary to select the most appropriate colonic cleansing agent and delivery regimen.
Core tip: Adequate bowel preparation is important for successful colonoscopic examination. A patient’s general health condition or concurrent medications may impair their ability to tolerate a certain cathartic agent, and mental or physical disabilities may preclude their ability to complete the ingestion regimen. While impaired health increases the risk of agent-related complications, failure to comply with bowel preparation instructions in general limits adequate cleansing of the bowel. Unremoved fecal matter occludes the colonoscopic view, necessitating repeat examination. This review discusses the special conditions encountered most frequently in the endoscopic clinic so that effective and safe bowel preparation agents/regimens can be chosen.