From the Guidelines
The osmotic micro-enema works best for constipation relief, particularly when the rectum is full, as it effectively softens the stool and stimulates bowel contractions. This is based on the evidence from the 2018 study published in the Annals of Oncology 1, which provides a comprehensive overview of enema types, their rationale for use, and potential adverse effects.
Key Considerations
- The osmotic micro-enema contains a combination of agents, including sodium lauryl sulfoacetate, sodium citrate, and glycerol, which work together to soften the stool and stimulate bowel contractions.
- The study highlights that the osmotic micro-enema is most effective when the rectum is full, as determined by digital rectal examination (DRE) 1.
- Other enema types, such as normal saline, soap solution, and hypertonic sodium phosphate enemas, may also be effective but have potential risks and adverse effects, such as water intoxication, chemical irritation, and abdominal discomfort 1.
Important Safety Considerations
- Enemas are contraindicated in patients with certain medical conditions, including neutropenia, thrombocytopenia, paralytic ileus, and recent colorectal or gynecological surgery 1.
- It is essential to use enemas judiciously and under medical supervision to minimize the risk of adverse effects and dependence.
Additional Recommendations
- For patients with constipation, a comprehensive approach that includes dietary modifications, hydration, and physical activity is recommended, rather than relying solely on enemas 1.
- The choice of enema should be individualized based on the patient's specific needs and medical history, and under the guidance of a healthcare professional.
From the Research
Enema Effectiveness
- The provided studies do not directly compare the effectiveness of different enemas, but rather discuss the efficacy of various laxatives, including stimulant laxatives like bisacodyl and senna, as well as osmotic laxatives like polyethylene glycol 3350 (PEG 3350) and lactulose 2, 3, 4, 5, 6.
- Bisacodyl, a stimulant laxative, has been shown to be effective in treating constipation, with a network meta-analysis concluding that it has similar efficacy to other laxatives for the primary endpoint of ≥3 complete spontaneous bowel movements (CSBM)/week and an increase of ≥1 CSBM/week over baseline 5.
- However, the long-term use of stimulant laxatives like bisacodyl has raised concerns about potential harmful colonic effects and carcinogenic risk, and the evidence base does not support their use for more than four weeks 6.
Laxative Comparison
- A study comparing the efficacy of senalin and bisacodyl in treating constipation in intensive care unit patients found that bisacodyl had a higher mean defecation frequency on the second day of treatment, but also had a higher prevalence of complications on the third day of treatment 2.
- Another study found that osmotic laxatives like PEG 3350 and lactulose are effective and safe for both long- and short-term treatment of pediatric functional constipation, while stimulant laxatives like senna and bisacodyl can be used as adjunct therapies in specific clinical scenarios 3.
- A systematic review of over-the-counter treatments for chronic constipation found that polyethylene glycol-based preparations and senna have good evidence supporting their use as first-line laxatives, while other agents like bisacodyl and sodium picosulfate have modest evidence supporting their use 4.