Bowel Preparations

Availability:

• Peg/Macrogol 10g, Fortrans
• Monobasic Sodium Phosphate 48%, Dibasic Sodium Phosphate 18%, Fleet
• Tab Bisacodyl 10mg
• Supp Bisacodyl 5mg / 10mg
• Glycerin 25% enema, Ravin
• Syrup Lactulose

Effectiveness

1. Enemas

• Evidence. The evidence is mostly anecdotal with no recent prospective trials (Grade IIIB).
• Recommendations. Use enemas in patients who present to endoscopy with a poor distal colon preparation and in patients with a defunctionalized distal colon

2. Bisacodyl

• used as an adjunct with high-volume balanced solution shortened the duration of whole gut irrigation, although no significant difference in colon cleansing was identified
• Bisacodyl and magnesium citrate are used as adjuncts to PEG solutions and have allowed for less volume of PEG necessary for colonic cleansing

3. PEG (electrolyte lavage solution)

• PEG is a nonabsorbable solution that should pass through the bowel without net absorption or secretion.
• Significant fluid and electrolyte shifts are therefore avoided.
• Large volumes (4 liters) are required to achieve a cathartic effect
• PEG is more effective and better tolerated
• PEG is safer than osmotic laxatives/NaP for patients with electrolyte or fluid imbalances, such as renal or liver insufficiency, congestive heart failure, or liver failure (Grade IA).
• Divided-dose PEG regimens (2–3 liters given the night before the colonoscopy and 1–2 liters on the morning of procedure) are acceptable alternative regimens that enhance patient tolerance
• Enemas, bisacodyl, and metaclopramide as adjuncts to the full volume of PEG have not been demonstrated to improve colonic cleansing or patient tolerance and are, therefore, unnecessary

4. Aqueous NaP (Fleet)

• Aqueous NaP is a low-volume hyperosmotic solution
• draws plasma water into the bowel lumen to promote colonic cleansing
• Significant fluid and electrolyte shifts can occur.
• NaP must be diluted before drinking to prevent emesis and must be accompanied by significant oral fluid to prevent dehydration
• Patients with compromised renal function, dehydration, hypercalcemia, or hypertension with the use of angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers (ARBs) have experienced phosphate nephropathy after ingestion
• Aqueous NaP colonic preparation is an equal alternative to PEG solutions except for pediatric and elderly patients, patients with bowel obstruction, and other structural intestinal disorders, gut dysmotility, renal failure, congestive heart failure, or liver failure (Grade IA).

References:

1. Consensus document on bowel preparation before colonoscopy. GASTROINTESTINAL ENDOSCOPY Volume 64, No. 1 : 2006
2. Bowel preparation for colonoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy 2013; 45: 142–150
3. Clinical Guideline for Adult Gastrointestinal Endoscopy-Bowel Preparation. NUS, NHS Trust, October 2015.