Bowel preparation

Abstract

Colonoscopy and radiological investigations of the large bowel require the bowel to be cleared of faeces. In addition to dietary restriction, patients are usually given a laxative, orally or rectally. Osmotic laxatives containing sodium phosphate are highly effective, but can cause severe electrolyte disturbances. Polyethylene glycol is an osmotic laxative which is less likely to cause this problem. It is given in an iso-osmotic solution, but patients have to drink several litres of fluid. Stimulant laxatives such as bisacodyl and sodium picosulfate are easy to use, but can also cause electrolyte disturbances.