Does Reglan (metoclopramide) work on the small intestine in patients who have undergone a colectomy?

Metoclopramide Efficacy in Small Intestine After Colectomy

Metoclopramide (Reglan) does work on the small intestine in patients who have undergone a colectomy, as it stimulates small intestinal transit and increases peristalsis of the duodenum and jejunum. 1

Mechanism of Action in the Small Intestine

Metoclopramide has specific effects on small intestinal motility that remain intact even after colectomy:

• It increases peristalsis of the duodenum and jejunum, resulting in accelerated intestinal transit 1
• It works by sensitizing tissues to the action of acetylcholine and blocking dopamine receptors 1
• Its effect on motility is not dependent on intact vagal innervation, making it effective even after surgical procedures 1
• It has minimal effect on the colon, so its small intestinal action remains relevant after colectomy 1

Clinical Applications After Colectomy

In patients who have undergone colectomy, metoclopramide can be particularly useful for:

• Managing small intestinal dysmotility that may persist or develop after surgery
• Addressing symptoms of nausea and vomiting related to small bowel dysfunction
• Potentially improving small intestinal transit time when delayed gastric emptying occurs

Important Considerations and Limitations

1. Contraindication after bowel anastomosis: Prokinetic drugs like metoclopramide are generally not recommended after a bowel anastomosis 2, which is an important consideration if the colectomy included an anastomosis.

2. Limited duration of use: The European Medicines Agency's Committee recommends against long-term use of metoclopramide due to potential side effects, particularly extrapyramidal reactions 2.

3. Alternative prokinetics: If metoclopramide is contraindicated or ineffective, other options may include:

   • Prucalopride (a selective 5HT4 receptor agonist) 2
   • Erythromycin (a motilin agonist) or azithromycin, which may be more effective for small bowel dysmotility 2
   • Octreotide, which may be beneficial when other treatments fail 2

4. Potential side effects: Common adverse reactions include restlessness, drowsiness, fatigue, and rarely extrapyramidal symptoms with high dosage or prolonged use 3.

Dosing Considerations

• Standard oral dosing applies, but treatment duration should be limited (typically 4-12 weeks) 3
• Parenteral administration should be limited to 1-2 days when possible 3
• In patients with chronic intestinal motility disorders, metoclopramide should be tried as part of a prokinetic trial 2

Monitoring and Follow-up

Monitor for:

• Improvement in symptoms related to small intestinal dysmotility
• Extrapyramidal side effects, especially in elderly patients
• QTc prolongation if used concurrently with other medications affecting cardiac conduction

In summary, metoclopramide remains an effective option for managing small intestinal dysmotility in patients who have undergone colectomy, but its use should be carefully considered in the context of the specific surgical procedure performed and potential contraindications.