Adjuncts to colonic cleansing before colonoscopy

Table 1 Summary of the currently used colonic preparation adjuncts reviewed in this study

Adjunct	Substance/functions/mechanism	Strengths	Weakness	Conclusion
Bisacodyl1	Diphenylmethane; stimulant laxative	Useful for bowel preparation with low-volume polyethylene glycol (PEG) solution; reduces nausea and provides comparable cleansing potency[4,5]	Rare complication risk of ischemic colitis[7,8]	Controversial results on its efficacy as an adjunct
Magnesium citrate2	Osmotic laxative	Useful for bowel preparation with low-volume PEG solution; superior to other adjuncts in efficacy[9] Cleansing effect is comparable to PEG; has fair patient compliance[12]	Use with caution in patients with poor renal function, due to increased risk of hypermagnesemia[17]	May be used to reduce the large-volume dose of PEG solution; generally considered a useful substitute to the main bowel cleansing agents[15]
Senna (sennoside)2	Pod or leaf of Senna alexandrina, stimulant laxatives	Useful for bowel preparation with low-volume PEG solution[23]	Risk of abdominal pain with high-dose; possible complication risk of ischemic colitis	Generally considered an adequate adjunctive agent
Simethicone1	Anti-gas, anti-flatulent	May be useful for lessening bubble formation[25]	Limited usefulness for strengthening colonic preparation[26]; some experts do not recommend its use[28]	Not widely used as an adjunct
Prokinetics1	Metoclopramide (dopamine antagonist)	Anti-emetic, anti-bloating effects	No apparent influence on colonic cleansing[29]; extrapyramidal symptoms occur with high-dose	May be useful for preventing or relieving nausea and bloating sensation
	Mosapride (5-HT4 receptor agonist), itopride (dopamine D2 receptor antagonist)	Stimulates colonic peristalsis[33,34]	Unknown	Potential as an alternative adjunct in geographic regions with market availability
Sports drink ingredient (Gatorade)	MiraLAX/Gatorade	Superior palatability and higher bowel preparation rates (i.e., cleaner bowel)[35,36]	Risk of inducing fluid- electrolyte disturbances due to its non-isoosmolarity	Potential alternative in available area

¹Recommendable agent;

²Fairly recommendable agent based on the collective findings from this literature review.