Abstract
Among various colonic cleansing methods in preparation for colonoscopy, whole gut lavage with balanced electrolyte solution containing polyethylene glycol (PEG) is considered a most successful one in its simplicity, efficacy, and patients' tolerance. In experimental animals, very large dose of PEG is known to produce toxicity. Although absorption of orally administered PEG from the human gastrointestinal tract is considered to be poor, it should be critically evaluated in order to confirm safety of this colonoscopy prepartion. We measured serum concentration of PEG 4000 in 7 subjects and urinary excretion of the same substance in 13 subjects who ingested up to 240 g of PEG 4000 for colonoscopy preparation. Blood samples were obtained before, immediately after, 1, 3, and 12 hours after ingestion of PEG 4000. In all samples collected from 6 subjects, PEG 4000 could not be detected, as it was below the quantitation limit (10 μg/ml). In one subject with hyperlipidemia, measurement was not possible due to cross reaction to serum lipids. Urine specimens were collected for 48 hours after the initiation of ingestion. Mean urinary excretion of PEG 4000 in 13 subject was 0.09%. These results indicate that absorption of PEG 4000 from the human gastrointestinal tract is minimal and that PEG 4000 is unlikely to produce toxicity at its ordinary usual dosage for colonoscopy preparation.
