title: Mechanism of action and toxicities of purgatives used for colonoscopy preparation.
abstract: BACKGROUND
  In developed countries, colonoscopy volume has increased dramatically over the past 15 years and is the principle method used to screen for colon cancer. Preparations used for colon cleaning have evolved over the past 30 years. Some preparations have been shown to be unsafe and are now used on a limited basis. There has been progress on limiting the volume required and on taste improvement.
  
  
  METHODS
  This review provides an account of preparations used from 1980 when PEG-based preparations became widely available, until the present day. The review highlights their mechanism of action and principle toxicities. The handling of solutes and solute-free fluid by the colon is also reviewed.
  
  
  RESULTS
  The reader will gain a perspective on the factors considered in developing colonic purgatives and the rationale for choosing selected preparations based on patient factors such as age, co-morbidities and concomitant medications.
  
  
  CONCLUSIONS
  Although generally safe and effective, colonic purgatives have both acute and permanent toxicities. The safest preparations utilize PEG combined with a balanced electrolyte solution. Limitations of this preparation center on the volume required and poor taste. Alternative formulations are now available; however, those using sodium phosphate have fallen out of favor due to a risk of renal toxicity.
authors.affiliation: Temple University School of Medicine, Department of Medicine, Section of Gastroenterology, Philadelphia, PA 19140, USA.
authors.forename: Margaret
authors.initials: M
authors.lastname: Adamcewicz
authors.forename: Dilip
authors.initials: D
authors.lastname: Bearelly
authors.forename: Gail
authors.initials: G
authors.lastname: Porat
authors.forename: Frank K
authors.initials: FK
authors.lastname: Friedenberg
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism; D002400:Cathartics / Q000627:therapeutic use / Q000633:toxicity*; D019343:Citric Acid / Q000378:metabolism; D003110:Colonic Neoplasms / Q000175:diagnosis; D003113:Colonoscopy / Q000379:methods; D006801:Humans; D054559:Hyperphosphatemia / Q000139:chemically induced; D006996:Hypocalcemia / Q000139:chemically induced; D009397:Nephrocalcinosis / Q000139:chemically induced*; D009942:Organometallic Compounds / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011300:Preoperative Care; D016032:Randomized Controlled Trials as Topic; D007507:Therapeutic Irrigation
chemical_list: D002130:Calcium Phosphates; D002400:Cathartics; D009942:Organometallic Compounds; D010710:Phosphates; D019343:Citric Acid; C020243:calcium phosphate; D001205:Ascorbic Acid; C110422:magnesium citrate; C018279:sodium phosphate