Hyperphosphatemia after sodium phosphate laxatives in low risk patients: prospective study.
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.
Casais
Marcela-Noemi
MN
Department of Anesthesia, Preoperative Evaluation Section, Hospital Italiano de Buenos Aires, Rivadavia 4965, 9C, Buenos Aires, Argentina. marcela.casais@hospitalitaliano.org.ar
Rosa-Diez
Guillermo
G
Pérez
Susana
S
Mansilla
Elina-Noemi
EN
Bravo
Susana
S
Bonofiglio
Francisco-Carlos
FC
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
D002400:Cathartics; D054368:Laxatives; D010710:Phosphates; C018279:sodium phosphate