sodium phosphates

Sodium phosphates, specifically the combination of monosodium phosphate (sodium dihydrogen phosphate) and disodium phosphate (disodium hydrogen phosphate), function as a potent saline osmotic laxative. When administered either orally or rectally, these salts are poorly absorbed from the gastrointestinal tract, creating an osmotic gradient that draws significant volumes of water into the intestinal lumen. This accumulation of fluid results in the softening of stool and an increase in intraluminal pressure, which triggers stretch receptors in the colon to stimulate peristalsis and facilitate rapid bowel evacuation. This combination is primarily utilized for bowel cleansing in preparation for colonoscopy, surgery, or radiological examinations. However, its use requires caution due to the potential for significant electrolyte shifts and the risk of acute phosphate nephropathy, particularly in patients with pre-existing renal impairment or those taking certain medications like ACE inhibitors or NSAIDs.

Brand names

OsmoPrepFleet EnemaVisicolPhospho-sodaSalixColoclens

Other names

monobasic sodium phosphate and dibasic sodium phosphatesodium biphosphate and sodium phosphatesodium dihydrogen phosphate and disodium hydrogen phosphatemonosodium phosphate + disodium phosphate