What is a Fleet (sodium phosphate) enema?

Fleet (Sodium Phosphate) Enema: Definition, Uses, and Safety Considerations

A Fleet enema is a hypertonic sodium phosphate solution used to treat constipation by both distending the rectum and stimulating rectal motility, but should be used with caution due to potential serious adverse effects including electrolyte disturbances and perforation. 1

What is a Fleet Enema?

Fleet enema is a commercially available sodium phosphate enema that:

• Contains hypertonic sodium phosphate solution
• Works through two primary mechanisms:
  • Distends the rectum
  • Stimulates rectal motility
• Is typically administered rectally for rapid relief of constipation
• Is available over-the-counter for home use

Mechanism of Action

The sodium phosphate in Fleet enemas creates an osmotic effect that:

1. Draws water into the large bowel
2. Softens stool
3. Increases pressure within the rectum
4. Stimulates peristalsis and bowel evacuation

Clinical Uses

Fleet enemas are primarily indicated for:

• Relief of acute constipation
• Bowel preparation before certain medical procedures
• Treatment when digital rectal examination identifies a full rectum or fecal impaction 1

Safety Profile

While adverse effects are reported as "uncommon" 1, several serious concerns exist:

• Electrolyte disturbances: Can cause severe hyperphosphatemia, hypernatremia, and hypocalcemia 2, 3
• Perforation risk: Documented cases of bowel perforation, especially in elderly patients 4
• Mortality risk: Studies have reported mortality rates as high as 45% in elderly patients experiencing complications 3
• Renal damage: Can cause acute kidney injury, particularly in patients with pre-existing renal impairment 2

Contraindications

Fleet enemas are contraindicated in patients with: 1

• Neutropenia or thrombocytopenia
• Paralytic ileus or intestinal obstruction
• Recent colorectal or gynecological surgery
• Recent anal or rectal trauma
• Severe colitis, inflammation or infection of the abdomen
• Toxic megacolon
• Undiagnosed abdominal pain
• Recent radiotherapy to the pelvic area
• Children under 2 years of age 5

Age-Specific Considerations

• Children: Should not be used in children under 2 years of age and used with extreme caution between ages 2-5 5
• Elderly: Higher risk of adverse events including perforation and electrolyte disturbances 4, 3

Alternatives to Fleet Enemas

Safer alternatives include:

• Normal saline enemas (less irritating to rectal mucosa) 1
• Tap water enemas (safer in high-risk patients) 2
• Docusate sodium enemas (soften stool by aiding water penetration) 1
• Bisacodyl enemas (promote intestinal motility) 1
• Oral laxatives such as polyethylene glycol (PEG) 6

Risk Reduction Strategies

To minimize risks when using Fleet enemas:

1. Assess for contraindications before administration
2. Use the smallest effective volume
3. Ensure proper positioning during administration
4. Monitor high-risk patients (elderly, renal impairment) for electrolyte disturbances
5. Consider safer alternatives for high-risk patients

Conclusion

While Fleet enemas can be effective for constipation relief, their use carries significant risks, particularly in vulnerable populations. The documented cases of severe metabolic derangements, perforation, and death suggest that safer alternatives should be considered whenever possible, especially in high-risk patients.