Aim To investigate the effects of sodium picosulphate (Picolax^®) oral bowel preparation on levels of serum urea, electrolytes and glucose in patients undergoing bowel preparation for barium enema.

Method A prospective, non-randomised, pre-test and post-test trial was conducted with 144 patients aged 34-87 years, who had agreed to undergo a barium enema. Changes in serum urea, sodium, potassium, magnesium and glucose following Picolax^® treatment were investigated.

Results There were statistically significant post-Picolax^® reductions in serum concentrations of urea (mean difference 0.556 (95 per cent confidence intervals (CI) 0.321-0.791) mmol/L), sodium (mean difference 1.299 (0.799-1.799) mmol/L) and potassium (mean difference 0.163 (0.0853-0.241) mmol/L). Similar findings were observed for sodium and urea when the sample was stratified according to age: under 60 years (n=56) or 60 years and over (n=88). However, there was no significant change in potassium in patients aged under 60 years.

Conclusion In normal circumstances, use of Picolax^® oral bowel preparation results in a statistically, but not clinically, significant reduction in concentration of serum urea, sodium and potassium.