What are the risks associated with using Fleet (bisacodyl) enema?

Fleet Enema Risks

Fleet enemas (sodium phosphate) carry significant risks of severe and potentially fatal metabolic complications, particularly electrolyte disturbances, and should be reserved for low-risk patients only after safer alternatives have failed. 1

Major Metabolic Risks

Life-Threatening Electrolyte Abnormalities

• Extreme hyperphosphatemia is the most serious complication, with phosphorus levels reported as high as 45.0 mg/dL (normal: 2.5-4.5 mg/dL), which can be fatal 2
• Severe hypocalcemia occurs secondary to hyperphosphatemia, with calcium levels dropping as low as 2.0 mg/dL, potentially causing tetany and coma 3, 2
• Hypernatremia and hypokalemia develop in most patients experiencing toxicity 2
• These disturbances can occur even with standard 133 mL doses, not just overdoses 2

Renal and Cardiovascular Complications

• Acute renal failure develops in virtually all patients with severe Fleet enema toxicity 2
• Calcium-phosphate crystals deposit within renal tubular lumens, causing acute kidney injury 2
• Cardiac complications include prolonged QT interval and potential arrhythmias from severe electrolyte imbalances 4
• Volume depletion and hypotension are common presenting features 2

Mortality Data

• A single-center case series reported a 45% mortality rate among 11 elderly patients who developed severe complications from Fleet enemas 2
• Most patients presented within 24 hours of administration 2

High-Risk Patient Populations

Absolute Contraindications

Fleet enemas are contraindicated in patients with: 5

• Neutropenia or thrombocytopenia (white blood cell count <0.5 cells/μL)
• 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

Use with Extreme Caution (or Avoid)

• Elderly patients are at markedly increased risk for severe complications 3, 2
• Renal insufficiency or chronic kidney disease patients cannot adequately excrete absorbed phosphate 3, 6
• Bowel dysfunction or poor gut motility increases absorption time and toxicity risk 3, 6
• Small intestinal disorders (including Hirschsprung's disease) predispose to complications 6
• Children under 2 years should never receive Fleet enemas; use only with extreme caution between ages 2-5 years 6

Common Adverse Effects (Even Without Toxicity)

Local Effects

• Anal or rectal burning and pain 5, 7
• Rectal discomfort and mild cramps 8
• Chemical irritation of mucous membranes 5

Gastrointestinal Effects

• Abdominal discomfort including cramps and abdominal pain 5, 7
• Short-lasting diarrhea 5, 7
• Ileus and intra-abdominal hypertension in severe cases 4
• Faintness and stomach discomfort 8

Safer Alternative Recommendations

First-Line Therapy

• Bisacodyl suppository 10 mg rectally is recommended as first-line therapy with onset in 15-60 minutes 1
• Bisacodyl enema 37 mL/10 mg is an alternative first-line option 1
• Tap water enemas are safer alternatives that prevent fatal complications in high-risk patients 3

When Fleet Enema May Be Considered

• Only as second-line therapy after first-line options fail 1
• Use standard dose of 133 mL rectally as a single dose only 1
• Maximum frequency once daily and only in patients without renal dysfunction 1
• Never use repeated doses due to cumulative electrolyte disturbance risk 1

Critical Safety Monitoring

Before Administration

• Assess for all contraindications listed above 5
• Evaluate renal function in elderly or at-risk patients 3, 2
• Confirm absence of bowel obstruction or dysfunction 3, 6

After Administration

• Monitor for symptoms within 24 hours: hypotension, altered mental status, seizures, tetany, or severe abdominal distention 3, 4, 2
• In high-risk patients who inadvertently receive Fleet enema, check serum calcium, phosphorus, sodium, potassium, and renal function 2
• Measure intra-abdominal pressure if progressive abdominal distention develops 4

Emergency Management

• Urgent hemodialysis may be required for severe hyperphosphatemia 2
• Intravenous calcium gluconate for symptomatic hypocalcemia 4
• Aggressive volume resuscitation for hypotension 2

Key Clinical Pitfall

The most dangerous pitfall is assuming Fleet enemas are benign because they are available over-the-counter and widely used. Standard doses in vulnerable populations can be lethal 2. The American Gastroenterological Association recommends Fleet enemas be used sparingly due to these significant risks 1.