What clinical trials exist comparing daily enema protocols to alternative constipation treatments in children and adults?
Executive summary
Randomized trials directly comparing daily enema protocols with alternative constipation treatments are limited and concentrated in pediatrics; the best-documented comparisons pit enemas">rectal disimpaction or maintenance enemas against high‑dose or maintenance oral polyethylene glycol (PEG) regimens in children, with mixed or inconclusive results and important methodological caveats [1] [2]. There is sparse long‑term randomized evidence that adding regular enemas to conventional maintenance therapy improves outcomes in severely constipated children, and the assembled reporting does not identify randomized trials in adults comparing routine daily enemas to other standard treatments [3] [4] [5].
1. Pediatric randomized comparisons: PEG versus enemas — small trials, mixed outcomes
A systematic review identified only two randomized controlled trials directly comparing PEG with enemas for rectal fecal impaction in children and concluded that current evidence does not permit a clear determination of superiority for either approach because of the limited number and low quality of trials [1] [2]. One principal RCT from Amsterdam enrolled 90 children (aged 4–16) and randomized them to PEG 3350 with electrolytes versus daily enemas for six days as disimpaction therapy, but both the original trial reports and the review highlighted unclear randomization, lack of blinding, uncertain allocation concealment and absent intention‑to‑treat analyses as important risks of bias [1]. The practical takeaway from these trials is that enemas can produce rapid rectal evacuation but superiority over high‑dose oral PEG is not established by high‑quality evidence in children [1] [2].
2. Adding enemas to maintenance therapy — one long randomized study with null incremental benefit
A randomized trial assessed regular rectal enemas as an adjunct to conventional maintenance treatment (education, behavioral strategies plus PEG) in severely constipated children over a 52‑week follow‑up and found no clear additional benefit of enemas over oral laxatives alone: the intervention arm’s one‑year success rate was 47.1% versus 36.1% in controls in the reported analysis [4] [3]. That trial has been interpreted as evidence that routine, long‑term use of enemas as maintenance therapy does not clearly improve outcomes for many children already on aggressive oral regimens, though the study population was highly selected and clinical practice varies [3] [4].
3. Emergency and solution‑selection trials — short‑term, often nonrandomized evidence
In emergency department settings where rapid symptom relief is the priority, multiple observational series and a few comparative studies have examined different enema solutions and immediate stool output rather than long‑term outcomes; these studies typically show no consistent advantage among common enema solutions (sodium phosphate, soap suds, milk‑and‑molasses or local compounding) for acute stool output, but most are retrospective and not designed to compare daily enema protocols to systemic therapies [6] [7]. A planned or small randomized trial comparing several enema types for immediate relief in children has been reported or registered, underscoring clinician interest in acute‑care choice of solution rather than maintenance scheduling [8] [6].
4. Nonrandomized comparisons and alternative approaches — nasogastric high‑dose oral laxatives and practice variation
Prospective cohort data exist comparing nasogastric high‑dose oral disimpaction to rectal enemas in children, reflecting real‑world practice where some centers prefer oral disimpaction as less invasive; that study is not randomized and therefore cannot definitively rank effectiveness versus enemas but reports similar clinical considerations and patient/parent burden outcomes [5]. Clinical pathways and expert guidelines acknowledge faster symptomatic relief with rectal disimpaction yet recommend oral approaches for disimpaction when feasible, partly driven by invasiveness and electrolyte concerns with certain enemas [9] [10].
5. Gaps, biases, and the absence of adult randomized evidence in the supplied reporting
The available randomized evidence in children is few, often small, and at risk of bias per the systematic review’s appraisal, leaving clinicians to balance speed of effect (enemas) against invasiveness and family burden [1] [2]. The provided sources do not identify randomized clinical trials in adults that compare daily enema protocols with alternative constipation treatments, and the reporting therefore cannot support claims about adult efficacy or safety of routine daily enemas relative to modern pharmacologic options [1] [4] [5]. High‑quality, adequately powered RCTs with standardized outcome definitions and attention to harms are needed in both children and adults to settle whether scheduled daily enemas offer meaningful advantage over oral laxatives or newer pharmacotherapies [1] [4].