Is oral Reglan (metoclopramide) effective for treating moderate to severe ileus?

Oral Metoclopramide is Not Effective for Moderate to Severe Ileus

Oral metoclopramide is not recommended for the treatment of moderate to severe ileus as there is no evidence supporting its effectiveness, and its mechanism of action makes it physiologically unsuitable for this condition.

Mechanism of Action and Pharmacology

Metoclopramide's mechanism of action explains why it is ineffective for ileus:

• Metoclopramide primarily increases upper gastrointestinal tract motility by sensitizing tissues to acetylcholine 1, 2
• It increases tone and amplitude of gastric contractions, relaxes the pyloric sphincter, and increases peristalsis of the duodenum and jejunum 1
• Critically, metoclopramide has "little, if any, effect on the motility of the colon or gallbladder" according to FDA labeling 1
• The onset of action is 30-60 minutes following oral administration, with effects persisting for 1-2 hours 1

Evidence Against Use in Ileus

The most recent and highest quality evidence specifically examining promotility agents for ileus comes from a 2019 practice management guideline from the Eastern Association for the Surgery of Trauma:

• A systematic review and meta-analysis found metoclopramide was not effective in expediting the resolution of ileus 3
• The guideline explicitly states they "cannot recommend for or against the use of metoclopramide to hasten the resolution of ileus" 3

This is supported by a prospective randomized trial that specifically examined metoclopramide for postoperative ileus:

• The study found no statistically significant difference in time to oral intake between patients who received metoclopramide and those who did not 4
• There was also no difference in the incidence of prolonged ileus between treatment groups 4

Management Recommendations for Ileus

For moderate to severe ileus, particularly in the context of Clostridium difficile infection with ileus, guidelines recommend:

• Intravenous metronidazole plus oral or rectal vancomycin for fulminant C. difficile with ileus 5
• If ileus is present, vancomycin can be administered per rectum (500 mg in approximately 100 mL normal saline per rectum every 6 hours as a retention enema) 5

For postoperative ileus, the evidence supports:

• Early enteral nutrition (EEN) to expedite resolution of ileus 3
• EEN facilitates return of normal bowel function, achieving enteral nutrition goals, and reducing hospital length of stay 3

Special Considerations and Caveats

1. While there are isolated case reports of metoclopramide helping with specific types of ileus (vincristine-induced ileus 6 and ileus with acute spinal cord injury 7), these are low-quality evidence and contradict the higher-quality systematic reviews and randomized controlled trials.

2. The physiological basis for metoclopramide's ineffectiveness in ileus is clear from its pharmacology - it primarily affects upper GI motility and has minimal effect on colonic motility 1, 2.

3. In cases of severe ileus, particularly with C. difficile infection, more aggressive approaches are needed, including consideration of surgical intervention for fulminant cases 5, 8.

4. Oral medications in general may have limited absorption in the setting of significant ileus, further reducing any potential benefit of oral metoclopramide.

In conclusion, based on the available evidence and understanding of metoclopramide's pharmacology, oral metoclopramide should not be used as a treatment for moderate to severe ileus.