Know the Ins and Outs of Bowel Preps

Colonoscopy prep is inadequate up to 25% of the time…which can lead to missed lesions, longer procedures, repeat tests, etc.

Recommend a prep based on preference, comorbidities, and cost. Any option is effective…if patients can tolerate and use it properly.

PEG with electrolytes is still the “gold standard,” especially when fluid or electrolyte shifts may be harmful…diuretic use, kidney or liver disease, heart failure, etc. But taste and volume can be issues.

If patients find 4 L daunting, consider a low-volume product (MoviPrep, Bi-PegLyte), which is similar in cost and may be better tolerated.

Or evidence suggests that 2 bisacodyl tabs and drinking just 2 L of the higher-volume 4 L jug can work as well as 4 L.

Non-PEG products (Pico-Salax, Purg-Odan) are also low-volume.

But these are hyperosmotic…and shouldn’t be used if fluid or electrolyte shifts are a concern. Also avoid these in patients on meds that may increase risk of kidney injury (ACEIs, ARBs, NSAIDs, etc).

PEG 3350 (Restoralax, etc) is also an option.

Recommend 238 g mixed in 2 L of a light-coloured sports drink, such as Gatorade…sometimes along with bisacodyl. It costs about $10…but has less electrolytes, which may lead to fluid and electrolyte loss.

Save magnesium citrate (Citro-Mag, etc) as a last resort…due to limited efficacy data and risk of high magnesium, especially in kidney disease or the elderly.

With any prep, recommend a split-dose regimen…taking half the night before and half 4 to 6 hours before the colonoscopy. This may get patients up early…but improves prep quality and tolerability.

Suggest other ways to make preps easier to swallow…chilling the solution, drinking through a straw to bypass taste buds, etc.