Dosing considerations in the use of sodium phosphate bowel preparations for colonoscopy

Ann Pharmacother. 2007 Sep;41(9):1466-75. doi: 10.1345/aph.1K206. Epub 2007 Jul 24.


Objective: To review dosing considerations and other treatment recommendations to maximize the efficacy, tolerability, and safety of sodium phosphate (NaP) preparations.

Data sources: Literature was accessed through PubMed (1990-May 2007) and abstracts from scientific meetings.

Study selection and data extraction: English-language publications including clinical trials and case reports were evaluated. Recent reports assessing newer bowel preparations containing reduced doses of NaP were reviewed to evaluate efficacy, tolerability, and safety.

Data synthesis: Among commonly administered bowel preparations for colonoscopy, NaP preparations are generally more effective and better tolerated compared with polyethylene glycol electrolyte lavage solution regimens. However, NaP preparations are contraindicated in specific patient populations, and clinicians must use effective screening mechanisms to select proper patients to receive NaP preparation for colonoscopy. Recently, cases of renal failure in patients with previously normal renal function have been reported after NaP preparation for colonoscopy, heightening concerns about the safety of these agents. Newer products contain reduced doses of NaP and may improve the safety and tolerability of NaP purgatives without compromising efficacy of colon cleansing. In addition, accumulating clinical data and/or rationale support split dosing of NaP products, wide intervals between doses, and aggressive hydration before and during bowel preparation and after the colonoscopy procedure.

Conclusions: Safe administration of NaP products requires rigorous attention to dosing considerations and other treatment recommendations, including administration of minimally effective doses of NaP, split-dosing schedules, and aggressive hydration.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Acute Kidney Injury / chemically induced
  • Cathartics / administration & dosage*
  • Cathartics / adverse effects
  • Colonoscopy*
  • Electrolytes / blood
  • Humans
  • Phosphates / administration & dosage*
  • Phosphates / adverse effects
  • Water-Electrolyte Balance


  • Cathartics
  • Electrolytes
  • Phosphates
  • sodium phosphate