How to manage functional ileus in patients on chronic Morphine Sulfate (MS Contin) therapy

Management of Functional Ileus in Patients on Chronic MS Contin Therapy

The most effective approach for managing functional ileus in patients on chronic morphine sulfate therapy is to discontinue the opioid medication and implement a supervised opioid withdrawal protocol with pain specialist involvement, as morphine is contraindicated in patients with gastrointestinal obstruction including paralytic ileus. 1, 2

Understanding the Problem

Chronic opioid use, including MS Contin (morphine sulfate controlled-release), is a common cause of functional ileus through several mechanisms:

• Direct inhibition of gastrointestinal motility
• Development of narcotic bowel syndrome
• Increased sphincter tone
• Decreased intestinal secretions

The FDA label for morphine sulfate explicitly states that it is contraindicated in "known or suspected gastrointestinal obstruction, including paralytic ileus" 1.

Management Algorithm

Step 1: Discontinue Contributing Medications

• Discontinue MS Contin through a gradual, supervised withdrawal protocol 2, 3
• Involve a pain specialist in this process whenever possible 2
• Replace with non-opioid analgesics:
  • Regular acetaminophen/paracetamol
  • NSAIDs if not contraindicated
  • Avoid anticholinergic agents which can worsen ileus 3

Step 2: Implement Supportive Measures

• Fluid and electrolyte management:

  • Administer isotonic IV fluids for dehydration 3
  • Monitor electrolytes, especially magnesium 3
  • Avoid fluid overload (limit weight gain to <3kg) 3

• Gastrointestinal decompression:

  • Consider nasogastric tube placement only for significant abdominal distention, vomiting, or respiratory compromise 3
  • A venting gastrostomy may reduce vomiting in severe cases 2

Step 3: Pharmacological Interventions

• Prokinetic agents:

  • Metoclopramide to stimulate upper GI motility 3
  • Consider alvimopan (μ-opioid receptor antagonist) to accelerate GI recovery while transitioning off opioids 3, 4

• Treatment of bacterial overgrowth:

  • Consider rifaximin for prolonged ileus with bacterial overgrowth 2, 3

Step 4: Nutritional Support

• Implement early oral nutrition once signs of resolving ileus appear 3
• If oral intake is inadequate:
  • Consider enteral nutrition via nasojejunal tube initially 2
  • If successful, consider more permanent feeding tube placement 2
  • Reserve parenteral nutrition for cases with significant malnutrition or when enteral nutrition fails 2, 3

Step 5: Non-Pharmacological Interventions

• Early mobilization to stimulate bowel function 3
• Position patient with head of bed elevated 30-45 degrees 3
• Consider chewing gum to stimulate gastrointestinal motility 3

Monitoring for Resolution

• Assess for:
  • Decreased abdominal distention
  • Return of bowel sounds
  • Passage of flatus/stool 3
• Monitor vital signs, urine output, blood glucose, electrolytes, and renal function 3

Important Caveats and Pitfalls

1. Avoid abrupt discontinuation of MS Contin in physically dependent patients, as this may lead to withdrawal syndrome and increased pain 1

2. Be cautious with alternative opioids - even switching to a different opioid may perpetuate ileus, though some patients may tolerate certain opioids better than others 2

3. Recognize that investigations of gut function may be unreliable in the presence of opioids 2

4. Consider multidisciplinary team involvement for complex cases, including gastroenterologist, pain specialist, and nutritionist 2

5. Optimize nutritional status before any surgical intervention 2, 3

By following this structured approach and prioritizing opioid discontinuation or reduction, most cases of functional ileus in patients on chronic MS Contin therapy can be effectively managed while maintaining adequate pain control through alternative methods.