Treatment of Chronic Constipation

Mechanism of Action

Lactulosa is a synthetic disaccharide that exerts an osmotic laxative effect in the colon to promote peristalsis, and its fermentation by bacteria produces gas, leading to abdominal distension and flatulence in patients with chronic constipation 1, 2
The American Gastroenterological Association considers lactulosa as an osmotic laxative for the treatment of chronic idiopathic constipation, but its use is limited by dose-dependent adverse effects such as distensión abdominal, flatulencia, and calambres abdominales 1, 2

The macrogol is a biologically inert and non-absorbable polymer that functions as an osmotic laxative, and it is associated with fewer adverse effects, such as vomiting and flatulence, compared to lactulosa 3, 4
The American College of Gastroenterology recommends the use of macrogol over lactulosa for the treatment of chronic constipation due to its superior efficacy and tolerability, especially in long-term management 5, 1

The American Gastroenterological Association and the American College of Gastroenterology consider macrogol as a first-line treatment for chronic constipation, and lactulosa may be considered if symptoms do not improve with fiber and over-the-counter laxatives 1, 5
The strength of evidence for macrogol is high, while the certainty of evidence for lactulosa is very low due to risk of bias and imprecision 1, 3

Macrogol is safe for long-term use in children, elderly, during pregnancy, and in the presence of secondary or irreversible organic constipation, and it is preferred over laxatives containing magnesium in patients with renal insufficiency 4
Lactulosa may not increase blood sugar levels in patients with type 2 diabetes mellitus who are mildly constipated and not dependent on insulin 1