Safety, efficacy, and patient tolerance of a three-dose regimen of orally administered aqueous sodium phosphate for colonic cleansing before colonoscopy

Background. Sodium phosphate, administered orally, is an effective, well-tolerated colonic cleansing agent. However, colonoscopic visualization is suboptimal in many patients after a conventional 2-dose regimen. This study assessed the safety, the efficacy, and patient tolerance of a 3-dose regimen of sodium phosphate. Methods: Patients without cardiac, renal, or hepatic insufficiency were randomized to precolonoscopy purgation with 3 (45 mL) doses vs. two doses of aqueous sodium phosphate administered orally. Hemodynamic measurements and serum and urine biochemical tests were obtained at baseline and after purgation. Tolerance of the bowel preparation and colonoscopic visualization were assessed via questionnaires. Results: Quality of colonic cleansing was significantly better with the 3-dose regimen compared with the 2-dose regimen (p < 0.0001). No clinically significant adverse event was detected in either group. Subclinical orthostasis was observed in 5% of patients given the 2-dose regimen vs. 3% of those who took the 3-dose regimen. Post-purgation hyperphosphatemia was greater in the 3-dose group vs. the 2-dose group (p = 0.0003). No other significant differences in biochemistry were noted between the groups. Patient tolerance of the 2-dose regimen was better than the 3-dose regimen (p = 0.0379). Conclusions: A 3-dose regimen of orally administered sodium phosphate provides superior colonic cleansing without compromising volume status or serum biochemistry but is associated with poorer overall patient tolerance compared with a conventional 2-dose regimen.