Intestinal and renal effects of low-volume phosphate and sulfate cathartic solutions designed for cleansing the colon: pathophysiological studies in five normal subjects.
Am J Gastroenterol
; 104(4): 953-65, 2009 Apr.
Article
in En
| MEDLINE
| ID: mdl-19240703
ABSTRACT
OBJECTIVES:
Ingestion of a concentrated low-volume phosphate solution produces copious diarrhea, which cleanses the colon, but it occasionally causes renal failure due to calcium phosphate precipitation in renal tubules. We hypothesized that a concentrated low-volume sulfate solution would be an equally effective cathartic, and that urine produced after sulfate would have less tendency to precipitate calcium salts than urine produced after phosphate.METHODS:
Hydrated subjects ingested 75 ml of phosphosoda or an equimolar dose of sulfate salts in a small volume of solution. Four liters of PEG (polyethylene glycol) lavage solution was the control. All solutions were administered in split doses, 10 h apart. Propensity of urine to precipitate at pH 6.4 (the pH of renal tubular fluid) was assessed by determining the minimal calcium concentration that caused precipitation.RESULTS:
Average diarrheal stool weight was 2,004 g after phosphate, 2,854 g after sulfate, and 3,021 g after PEG (P<0.001). Average calcium concentration (in mg/dl) required to induce urine precipitation at pH 6.4 was 43 after PEG, 10 after PO(4), and 187 after SO(4) (P=0.009).CONCLUSIONS:
(i) In equimolar doses, sulfate produced 42% more diarrheal stool weight than phosphate. (ii) Phosphate increased the propensity for calcium salt precipitation in urine at pH 6.4, whereas sulfate did not. (iii) These results suggest that a hypertonic low-volume sulfate solution would be an effective cathartic for colon cleansing and that sulfate-induced catharsis would be less likely than phosphate catharsis to produce calcium salt deposition in renal tubules.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phosphates
/
Sulfates
/
Cathartics
/
Colonoscopy
/
Intestine, Large
/
Kidney
Limits:
Adult
/
Humans
/
Male
Language:
En
Journal:
Am J Gastroenterol
Year:
2009
Type:
Article
Affiliation country:
United States