Laxatives for the management of constipation in people receiving palliative care.

Systematic review of randomized trials in adults with advanced illness receiving palliative care, mainly cancer, in hospice, hospital, and outpatient settings in Canada, Britain, Spain, and India. The evidence base consisted of a small number of small parallel-group and cross-over studies.

The review assessed short-term oral laxative regimens used in palliative care, including senna, lactulose, misrakasneham, co-danthramer plus poloxamer, magnesium hydroxide plus liquid paraffin, and docusate plus senna. Most trials compared one active laxative regimen with another active laxative or with placebo added to senna, with treatment durations ranging from 10 days to 27 days.

Overall, the laxatives studied in palliative care appeared to have broadly similar effectiveness, and no optimal agent was identified. Evidence was limited by small trials and inconsistent reporting, and there was no evaluation of polyethylene glycol or rectal interventions. In one crossover hospice study, lactulose plus senna produced significantly higher stool frequency than co-danthramer plus poloxamer in 17 participants receiving at least 80 mg/day strong opioids (P < 0.01), with rescue laxatives needed in 19/51 versus 9/51 and six diarrhoea events versus none. In Tarumi 2013, adding docusate to senna did not improve the chance of a bowel movement on 50% of study days (OR 0.52, 95% CI 0.17 to 1.57), although stool consistency differed (P = 0.001); additional laxatives were still needed in 68.6% versus 74% of participants. Another trial found no statistical difference in satisfactory bowel movements between misrakasneham and senna.

The evidence base was sparse, with only a small number of small randomized trials and limited power to detect clinically important differences. Follow-up was short, several outcomes were inconsistently reported, and tolerability, patient preference, and cost were under-evaluated. Findings are indirect for other laxatives and settings because polyethylene glycol and rectal interventions were not studied, and extrapolation from non-palliative populations may be unreliable.