Switching from stimulant laxatives to macrogol-4000 in patients with chronic constipation

AIM: to evaluate the efficacy and safety of a stepwise transition from stimulant laxatives to macrogol-4000 in colorectal patients with chronic constipation, including preoperative bowel preparation for colonic surgery.

PATIENTS AND METHODS: a single-center prospective cohort pilot study with a “before–after” design was conducted. Ninety-three patients (82 women, 11 men; mean age 65.0 ± 14.2 years) were enrolled between January and December 2025, all with chronic constipation and long-term self-administration of stimulant laxatives (median duration 5.0 years; interquartile range 1.0–15.0; range 0.5–35.0 years). Functional constipation was the leading diagnosis 78/93 (83.9%), whereas constipation-predominant irritable bowel syndrome and dolichocolon accounted for 6/93 (6.5%) and 9/93 (9.7%) cases, respectively. The transition protocol comprised a 4-phase tapering scheme of stimulant laxative dose reduction combined with standard-dose macrogol-4000 over 3–8 weeks. Primary endpoints: complete discontinuation of stimulant laxatives at transition completion; change in stool consistency (Bristol Stool Scale, BSS) and stool frequency from baseline to transition completion (3–8 weeks); incidence of therapy-related adverse events. Exploratory endpoint: bowel preparation quality assessed by Boston Bowel Preparation Scale (BBPS) in patients with colonic polyps.

RESULTS: according to the intention-to-treat analysis (all 93 patients), complete discontinuation of stimulant laxatives at transition completion was achieved in 76/93 (81.7%; 95% CI [72.5; 88.9]). Among compliant patients (76/93; 81.7%) who completed the protocol as prescribed (≥ 80% adherence), discontinuation was achieved in 76/76 (100.0%; 95% CI [95.2; 100.0]). Median BSS score significantly improved from 1.0 (interquartile range 1.0–2.0) to 3.0 (2.0–4.0) (p < 0.0001 by Wilcoxon signed-rank test). The proportion of patients with normal stool (BSS 3–4) increased from 4/73 (5.5%) to 51/73 (69.9%) (relative risk 12.7; 95% CI [4.8; 33.6]; p < 0.0001 by McNemar's test). Mean stool frequency increased from 0.68 ± 0.21 to 1.11 ± 0.33 bowel movements per day (p < 0.0001). Therapy-related adverse events occurred in 4/93 (4.3%) patients (mild bloating, not requiring therapy discontinuation). Normalization of colonic transit (complete laxative independence) was achieved in 16/76 (21.1%) of patients. Mean transition duration was 5.2 ± 1.2 weeks. No diarrhea (BSS ≥ 6) was observed upon therapy completion. In 15/15 (100%) patients with colonic polyps, transition to macrogol-4000 provided adequate bowel preparation for colonoscopy and subsequent polypectomy without stimulant laxatives (median BBPS score 8.0 [7.0; 9.0], range 6–9).

CONCLUSION: the stepwise protocol for replacing stimulant laxatives with macrogol-4000 demonstrates high efficacy and safety in colorectal patients. Macrogol-4000 provides reliable constipation correction and adequate preparation for diagnostic and surgical interventions on the colon. These results justify a randomized controlled trial to verify the findings

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