title: Hyperphosphatemia after sodium phosphate laxatives in low risk patients: prospective study.
abstract: OBJECTIVE
  To establish the frequency of hyperphosphatemia following the administration of sodium phosphate laxatives in low-risk patients.
  
  
  METHODS
  One hundred consecutive ASA I-II individuals aged 35-74 years, who were undergoing colonic cleansing with oral sodium phosphate (OSP) before colonoscopy were recruited for this prospective study.
  
  
  METHODS
  congestive heart failure, chronic kidney disease, diabetes, liver cirrhosis, intestinal obstruction, decreased bowel motility, increased bowel permeability, and hyperparathyroidism. The day before colonoscopy, all the participants entered a 24-h period of diet that consisted of 4 L of clear fluids with sugar or honey and 90 mL (60 g) of OSP in two 45-mL doses, 5 h apart. Serum phosphate was measured before and after the administration of the laxative.
  
  
  RESULTS
  The main demographic data (mean +/- SD) were: age, 58.9 +/- 8.4 years; height, 163.8 +/- 8.6 cm; weight, 71 +/- 13 kg; body mass index, 26 +/- 4; women, 66%. Serum phosphate increased from 3.74 +/- 0.56 to 5.58 +/- 1.1 mg/dL, which surpassed the normal value (2.5-4.5 mg/dL) in 87% of the patients. The highest serum phosphate was 9.6 mg/dL. Urea and creatinine remained within normal limits. Post-treatment OSP serum phosphate concentration correlated inversely with glomerular filtration rate (P < 0.007, R(2) = 0.0755), total body water (P < 0.001, R(2) = 0.156) and weight (P < 0.013, R(2) = 0.0635).
  
  
  CONCLUSIONS
  In low-risk, well-hydrated patients, the standard dose of OSP-laxative-induced hyperphosphatemia is related to body weight.
authors.affiliation: Department of Anesthesia, Preoperative Evaluation Section, Hospital Italiano de Buenos Aires, Rivadavia 4965, 9C, Buenos Aires, Argentina. marcela.casais@hospitalitaliano.org.ar
authors.forename: Marcela-Noemi
authors.initials: MN
authors.lastname: Casais
authors.forename: Guillermo
authors.initials: G
authors.lastname: Rosa-Diez
authors.forename: Susana
authors.initials: S
authors.lastname: Pérez
authors.forename: Elina-Noemi
authors.initials: EN
authors.lastname: Mansilla
authors.forename: Susana
authors.initials: S
authors.lastname: Bravo
authors.forename: Francisco-Carlos
authors.initials: FC
authors.lastname: Bonofiglio
mesh_terms: D000328:Adult; D000368:Aged; D002400:Cathartics / Q000009:adverse effects / Q000737:chemistry; D005260:Female; D006801:Humans; D054559:Hyperphosphatemia / Q000139:chemically induced*; D054368:Laxatives / Q000009:adverse effects / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000009:adverse effects / Q000737:chemistry; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D002400:Cathartics; D054368:Laxatives; D010710:Phosphates; C018279:sodium phosphate