title: Randomised clinical trial: Polyethylene glycol 3350 with sports drink vs. polyethylene glycol with electrolyte solution as purgatives for colonoscopy--the incidence of hyponatraemia.
abstract: BACKGROUND
  Polyethylene glycol 3350 plus sports drink (PEG-SD) is a hypo-osmotic purgative commonly used for colonoscopy, though little safety data are available.
  
  
  OBJECTIVE
  To evaluate the effect of PEG-SD on serum sodium (Na) and other electrolytes compared with PEG-electrolyte solution (PEG-ELS).
  
  
  METHODS
  We performed a single center, prospective, randomised, investigator-blind comparison of PEG-ELS to PEG-SD in out-patients undergoing colonoscopy. Laboratories were obtained at baseline and immediately before and after colonoscopy. The primary endpoint was development of hyponatraemia (Na <135 mmol/L) the day of colonoscopy. Changes in electrolyte levels were computed as the difference between the lowest value on the day of colonoscopy and baseline. Purgative tolerance and efficacy were assessed.
  
  
  RESULTS
  A total of 389 patients were randomised; 364 took purgative and had baseline and day of colonoscopy labs (180 PEG-SD, 184 PEG-ELS). The groups were well matched except for a higher fraction of women and Blacks in PEG-ELS. Seven patients (3.9%) in PEG-SD and four patients (2.2%) in PEG-ELS developed hyponatraemia (OR = 1.82, 95% CI: 0.45-8.62, P = 0.376). Changes in electrolytes from baseline were small but significantly worse with PEG-SD for sodium, potassium and chloride (P = 0.001, 0.012, 0.001, respectively). Preparation completion, adverse events, and overall colon cleansing were similar between the groups, but PEG-ELS had more excellent preparations (52% vs. 30%; P = 0.001).
  
  
  CONCLUSIONS
  Greater, but very modest, electrolyte changes occur with PEG-SD. Hyponatraemia is infrequent with both purgatives. A significant increase in hyponatraemia was not identified for PEG-SD vs. PEG-ELS, but the sample size may have been inadequate to identify a small, but clinically important difference. ClinicalTrials.gov identifier NCT01299779.
authors: Division of Gastroenterology and Hepatology, Thomas Jefferson University Hospital, Philadelphia, PA, USA.
authors: R
authors: R
authors: Matro
authors: C
authors: C
authors: Daskalakis
authors: D
authors: D
authors: Negoianu
authors: L
authors: L
authors: Katz
authors: C
authors: C
authors: Henry
authors: M
authors: M
authors: Share
authors: D
authors: D
authors: Kastenberg
mesh_terms: D000368:Aged; D001628:Beverages; D002400:Cathartics / Q000009:adverse effects* / Q000627:therapeutic use; D002712:Chlorides / Q000097:blood; D003113:Colonoscopy; D004573:Electrolytes / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000139:chemically induced*; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D011092:Polyethylene Glycols / Q000009:adverse effects* / Q000627:therapeutic use; D011188:Potassium / Q000097:blood; D012964:Sodium / Q000097:blood
chemical_list: D002400:Cathartics; D002712:Chlorides; D004573:Electrolytes; D011092:Polyethylene Glycols; D012964:Sodium; D011188:Potassium