Is a soap suds enema a recommended treatment for constipation?

Soap Suds Enema for Constipation

Soap suds enemas are a recognized treatment option for constipation, but should be reserved as second-line therapy when oral laxatives fail after several days, or as first-line therapy specifically when digital rectal examination identifies a full rectum or fecal impaction. 1

When to Use Soap Suds Enemas

Appropriate indications include:

• Failure of oral laxative therapy after several days 1
• Digital rectal examination confirms full rectum or fecal impaction 1
• Prevention of fecal impaction in high-risk patients 1

The ESMO guidelines specify that soap solution enemas should use a 1:200 ratio (1 mL of mild liquid soap per 200 mL of solution) with a total volume of 1000 mL. 1

Absolute Contraindications

Do not administer soap suds enemas in patients with: 1, 2

• Neutropenia or thrombocytopenia (risk of bleeding complications and life-threatening infections)
• Paralytic ileus or intestinal obstruction (can precipitate perforation)
• Recent colorectal or gynecological surgery (risk of anastomotic dehiscence)
• Recent anal or rectal trauma
• Severe colitis, inflammation, or infection of the abdomen
• Toxic megacolon (may precipitate perforation)
• Undiagnosed abdominal pain (may mask serious underlying conditions)
• Recent radiotherapy to the pelvic area (tissue fragility)

Patients on therapeutic anticoagulation or with coagulation disorders face increased risk of bleeding complications and intramural hematomas. 1, 2

Known Risks and Adverse Events

Chemical irritation of mucous membranes is the primary concern with soap suds enemas. 1 Additional risks include:

• Intestinal perforation (suspect if abdominal pain occurs during or after administration) 1, 2
• Rectal mucosal damage 1
• Bacteremia from mucosal trauma 1, 2
• Water intoxication if large volume enemas are retained 1, 2

Research data shows that perforation and mortality are not rare complications—one study documented a 1.4% perforation rate and 3.9% 30-day mortality rate in elderly patients receiving enemas for acute constipation. 3

Preferred First-Line Alternatives

Oral laxatives should be attempted first: 1

• Osmotic laxatives: Polyethylene glycol (PEG), lactulose, or magnesium/sulfate salts 1
• Stimulant laxatives: Senna, cascara, bisacodyl, or sodium picosulfate 1

Magnesium and sulfate salts require caution in renal impairment due to hypermagnesemia risk. 1

Administration Considerations

Small volume self-administered enemas are preferred when enemas are necessary. 1 Large volume clinician-administered enemas (like soap suds enemas) should only be administered by experienced healthcare professionals. 1

Pediatric data suggests soap suds enemas can be efficacious (82% success rate) and relatively safe in children with fecal impaction, though adverse events including abdominal pain (5%) and nausea/vomiting (4%) do occur. 4 However, this does not negate the serious risks in vulnerable adult populations, particularly the elderly and immunocompromised.

Clinical Algorithm

1. Assess for contraindications (neutropenia, thrombocytopenia, obstruction, recent surgery/trauma, severe colitis, toxic megacolon, undiagnosed pain, recent pelvic radiation) 1, 2
2. Perform digital rectal examination to confirm full rectum or impaction 1
3. If rectum is full/impacted and no contraindications exist: Enemas become first-line therapy 1
4. If rectum is not full: Trial oral laxatives (osmotic or stimulant) for several days first 1
5. Only proceed to soap suds enema if oral therapy fails and contraindications are absent 1

Critical Pitfall to Avoid

Never administer enemas to patients with suspected or confirmed bowel obstruction—this can precipitate perforation, exacerbate obstruction, and cause life-threatening complications. 2 Plain abdominal X-ray or CT scan should be obtained if obstruction is suspected before any enema administration. 2