Fleet Enema Onset of Action
A Fleet (bisacodyl) enema typically produces a bowel movement within 15 minutes to 1 hour after administration. 1
Timing and Mechanism
- Bisacodyl enemas work by promoting intestinal motility through water passage into the intestinal lumen, with an expected onset of 15 minutes to 1 hour. 1
- The docusate sodium component (if present in combination formulations) takes 5-20 minutes to soften stool by aiding water penetration. 2
- For optimal effect, bisacodyl enemas should be retained for at least a few minutes to allow the medication to stimulate rectal motility. 2
Clinical Context for Use
- Bisacodyl enemas are indicated as first-line therapy when digital rectal examination identifies a full rectum or fecal impaction. 2, 3
- They are preferred over oral laxatives when rapid bowel evacuation is needed, as enemas work more quickly than oral agents. 2
- The typical administration protocol involves giving the enema 2 hours before a procedure (such as flexible sigmoidoscopy), with most patients experiencing a bowel movement within 10 minutes. 4, 5
Important Safety Considerations
Bisacodyl enemas are contraindicated in patients with: 2, 3
- 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
Common Adverse Effects
- Abdominal discomfort including cramps and abdominal pain is common with bisacodyl enemas. 2, 6
- Short-lasting diarrhea may occur. 2
- Anal or rectal burning and pain can develop. 2
Practical Administration Tips
- Patients should be counseled that the effect typically occurs within 15-60 minutes, so they should remain near toilet facilities during this window. 1
- If no bowel movement occurs within 1 hour, reassessment for impaction or obstruction is warranted. 2
- The enema should be administered by an experienced healthcare professional when dealing with severe impaction or in high-risk patients. 2