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Effects of lactulose and polyethylene glycol on colonic transit
Author(s) -
Fritz E.,
Hammer H. F.,
Lipp R. W.,
Högenauer C.,
Stauber R.,
Hammer J.
Publication year - 2005
Publication title -
alimentary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.308
H-Index - 177
eISSN - 1365-2036
pISSN - 0269-2813
DOI - 10.1111/j.1365-2036.2005.02244.x
Subject(s) - lactulose , laxative , polyethylene glycol , medicine , gastroenterology , transit time , ingestion , chemistry , biochemistry , constipation , transport engineering , engineering
Summary Background : The effects of lactulose and polyethylene glycol on colonic transit are poorly established. Aim: To assess the effects of these laxatives on colonic transit in normal subjects. Methods : Colonic transit (mean residence time, cumulative counts in stool, counts remaining in the proximal or distal colon) was measured scintigraphically in normal subjects on the second and third day of a 3‐day ingestion of 67–134 g/day lactulose, or 59 g/day polyethylene glycol. Results : At similar stool weight (lactulose: 653 ± 120 g/day; polyethylene glycol: 522 ± 66 g/day), transit was significantly slower during 99 g/day lactulose when compared with 59 g/day polyethylene glycol; this was most pronounced in the distal colon (mean residence time: lactulose – 403 ± 55 min; polyethylene glycol – 160 ± 41.9 min). Short chain fatty acid concentration in 24‐h stool correlated significantly with counts remaining in the distal colon at 12 h( r = 0.79, P = 0.001). Increasing lactulose doses were significantly associated with increasing stool weight ( r = 0.79) and shorter mean residence time in the total ( r = −0.56) and distal colon ( r = −0.64). The sum of faecal carbohydrates plus short chain fatty acids was associated with stool weight ( r = 0.95, P < 0.001). Conclusion : Lactulose accelerates colonic transit. However, compared with polyethylene glycol, transit during lactulose is prolonged.