Sodium phosphate tablets preferred over PEG solution for bowel cleansing
Sodium phosphate (NaP) tablets for bowel preparation prior to colonoscopy are safe, better tolerated by patients, and provide equivalent and possibly superior colon cleansing compared with standard polyethylene glycol (PEG) solution, a Korean study has found.
In the investigator-blinded, controlled study, 62 healthy Korean adults undergoing elective colonoscopy were randomized to receive NaP regimen (32 NaP tablets in divided doses) or standard PEG solution (4 L) for bowel preparation. Results showed no significant difference in total Ottawa Bowel Preparation Quality Scale (OBPQS) score between the NaP and PEG groups (4.3 vs 5.4; p=0.071). Fluid scores (fluid quantity in the entire colon), however, were significantly better with NaP vs PEG upon detailed analysis of individual OBPQS scores (0.1 vs 0.6; p<0.001). A significantly higher proportion of patients in the NaP group achieved adequate bowel preparation, defined as a total OBPQS score of ≤4 (62.5 vs 33.3 percent; p=0.022). [Yonsei Med J 2014;55:1542-1555]
“Higher satisfaction with the given bowel cleansing regimen was reported by patients in the NaP vs PEG group [8.5 vs 5.5 out of 10 on a visual analogue scale; p<0.001], and significantly more patients who used NaP indicated willingness to repeat the same regimen in the future [93.8 vs 30.0 percent; p<0.001]. A less burdensome bowel preparation regimen could lead to increased population participation in colorectal screening programmes,” reported lead author Dr Seung-Hwa Lee, of the Ajou University School of Medicine, Suwon, Korea, at the Asian Pacific Digestive Week 2017 held recently in Hong Kong.
The PEG regimen has been regarded as the gold standard for bowel cleansing, but the need to ingest a large volume as well as the unpleasant smell and taste of PEG frequently lead to poor patient compliance, resulting in inadequate bowel preparation.
“Adequate bowel preparation is essential for swift and complete examination of the entire colorectal mucosa with minimal complication to avoid missing pathologic lesions during colonoscopy,” said Lee.
“Low-volume fluid and efficacious NaP regimens are popular alternative methods for bowel preparation. However, potential associated risks include electrolyte imbalances, irreversible renal dysfunction and acute phosphate nephropathy,” Lee explained.
The most common adverse events experienced by patients in the study were nausea, vomiting, abdominal pain, and bloating/distension. No significant differences were observed between the two groups for abdominal pain and bloating, but nausea and vomiting were more frequent in patients who used PEG (50.0 vs 25.0 percent [p=0.042] and 43.3 vs 12.5 percent [p=0.007], respectively).
Significant fluctuations in serum chemistry and electrolytes were noted in both groups after bowel cleansing. Patients’ potassium and total calcium levels were significantly decreased from baseline in the NaP vs PEG group (-0.66 mEq/L and -0.45 mg/dL, respectively [both p<0.001] vs -0.21 mEq/L [p=0.004] and -0.01 mg/dL [p=0.963]), while inorganic phosphorus levels were significantly elevated in the NaP group (+1.58 mg/dL [p<0.001] vs +0.13 mg/dL [p=0.18]).
“However, the mean changes from baseline were generally mild and transient, and none of the changes resulted in serious complications or adverse events. On follow-up laboratory tests, these changes were found to have normalized,” noted Lee.
“As our sample size was small and included only outpatients without serious comorbidities, further multicentre, large-scale studies are needed to confirm these findings,” said Lee.