What are the treatment options for opioid-induced constipation?

Treatment Options for Opioid-Induced Constipation

For opioid-induced constipation (OIC), start with a prophylactic bowel regimen using stimulant laxatives with or without stool softeners, and escalate to peripherally acting mu-opioid receptor antagonists (PAMORAs) for refractory cases. 1

First-Line Management

Prophylactic Measures

• Begin preventive treatment at the same time as opioid therapy:
  • Stimulant laxatives (senna, bisacodyl) are preferred first-line agents 1
  • Polyethylene glycol (PEG) with water twice daily is an effective option 1
  • Avoid bulk-forming laxatives (psyllium, fiber supplements) as they are ineffective for OIC and may worsen constipation 1

Lifestyle Modifications

• Increase fluid intake to at least 8 glasses of water daily
• Gradually increase dietary fiber to 20-25g per day (unless contraindicated)
• Increase physical activity within patient limits
• Optimize toileting habits:
  • Establish a regular schedule
  • Ensure privacy and comfort
  • Use a footstool to elevate knees above hips 1

Second-Line Management (Refractory OIC)

For patients who fail to respond to first-line laxatives, consider:

Peripherally Acting Mu-Opioid Receptor Antagonists (PAMORAs)

• Naloxegol (Movantik®): FDA-approved for OIC in adult patients with chronic non-cancer pain 2

  • Dosing: 25 mg once daily (or 12.5 mg if unable to tolerate higher dose)
  • Contraindicated in patients with:
    • Known or suspected gastrointestinal obstruction
    • Risk of recurrent obstruction
    • History of gastrointestinal perforation 2

• Methylnaltrexone: 0.15mg/kg subcutaneously every other day 1

  • Note: Subcutaneous methylnaltrexone has shown superior efficacy compared to other interventions in some studies

Other Prescription Options

• Lubiprostone: Effective for OIC but associated with increased risk of adverse events 1
• Naldemedine: Effective for OIC but may increase adverse events 3

Monitoring and Assessment

• Use the Bowel Function Index to assess severity and monitor response:

  • Ease of defecation
  • Feeling of incomplete bowel evacuation
  • Personal judgment of constipation
  • Score ≥30 indicates clinically significant constipation requiring escalation of therapy 1

• Reassess treatment efficacy within 2-4 weeks of initiating therapy

• Goal: Achieving one non-forced bowel movement every 1-2 days 1

Important Precautions

• PAMORAs are contraindicated in patients with:

  • Gastrointestinal perforation risk
  • Mechanical bowel obstruction 1, 2

• Monitor for adverse effects with naloxegol:

  • Abdominal pain (21% with 25mg dose)
  • Diarrhea (9%)
  • Nausea (8%)
  • Potential opioid withdrawal symptoms (3% with 25mg dose) 2

• Patients on methadone may experience higher frequency of gastrointestinal adverse reactions with PAMORAs than those on other opioids 2

• If severe abdominal pain or diarrhea develops with naloxegol, discontinue therapy and consider restarting at 12.5 mg once daily if appropriate 2

Special Considerations

• For malignant bowel obstruction, opioid analgesics remain appropriate for pain control despite potentially exacerbating ileus 1
• In this context, adjunctive medications may include:
  • Anticholinergic agents (scopolamine, hyoscyamine, glycopyrrolate)
  • Octreotide to reduce secretions
  • H2 blockers to reduce gastric secretions
  • Corticosteroids to reduce inflammation 1