What to prescribe for opioid-induced constipation in a patient with a history of diverticulitis and possible bowel obstruction that resolved spontaneously?

Management of Opioid-Induced Constipation in a Patient with History of Diverticulitis and Resolved Bowel Obstruction

In this patient with prior diverticulitis and resolved bowel obstruction, start with prophylactic stimulant laxatives (senna or bisacodyl) combined with osmotic laxatives (polyethylene glycol), but absolutely avoid peripherally acting mu-opioid receptor antagonists (PAMORAs) due to the contraindication in patients at risk of recurrent obstruction. 1, 2

Critical Safety Consideration

PAMORAs (naloxegol, naldemedine, methylnaltrexone) are absolutely contraindicated in this patient. The FDA labeling for naloxegol explicitly states it is contraindicated in patients with known or suspected gastrointestinal obstruction or in patients at risk of recurrent obstruction 2. Your patient's history of possible bowel obstruction and diverticulitis places them squarely in this high-risk category. Cases of gastrointestinal perforation, including fatal cases, have been reported with PAMORA use in patients with diverticular disease 2.

First-Line Treatment Strategy

Begin prophylactic laxatives immediately when starting opioids, as tolerance to constipation does not develop: 1, 3

• Stimulant laxative: Senna 2 tablets every morning (can increase to maximum 8-12 tablets per day) or bisacodyl 5-15 mg daily 1
• Osmotic laxative: Polyethylene glycol (PEG) 17 grams in 8 oz water once to twice daily 1, 3
• Increase laxative doses proportionally when opioid doses are increased 1, 3

The combination of stimulant and osmotic laxatives is more effective than either alone, and notably, adding stool softeners like docusate to stimulant laxatives is actually less effective than stimulant laxatives alone 3. Avoid fiber supplements (psyllium/Metamucil) as they are ineffective for opioid-induced constipation 1, 3.

Target and Monitoring

Aim for one non-forced bowel movement every 1-2 days 1, 3. Monitor daily for bowel movements, abdominal distension, and pain 4. Use the Bowel Function Index to objectively assess severity and treatment response 3.

Escalation Strategy if Constipation Persists

Before escalating therapy, always reassess to rule out bowel obstruction or impaction: 1, 4

• Perform digital rectal examination to identify distal fecal impaction 4
• Assess for signs of obstruction (absent bowel sounds, severe distension, vomiting) 4

Second-line interventions (if no bowel movement within 24-48 hours): 1

• Add or increase stimulant laxatives: Bisacodyl 10-15 mg daily to three times daily 3
• Add additional osmotic laxatives: Magnesium hydroxide 30-60 mL daily, lactulose 30-60 mL daily, or sorbitol 30 mL every 2 hours × 3 then as needed 1
• Consider rectal interventions: Bisacodyl suppository 10 mg or glycerin suppository 4, 3
• If impaction is present, perform digital fragmentation and extraction, followed by Fleet enema or tap water enema (500-700 mL) 4

Third-line option (with extreme caution in this patient): 1, 3

• Prokinetic agent: Metoclopramide 10-20 mg PO four times daily may be considered, though use cautiously given risk of tardive dyskinesia and the fact that it doesn't address the underlying opioid mechanism 1, 3

Alternative Pain Management Strategies

Consider multimodal analgesia to reduce opioid requirements: 4

• Scheduled acetaminophen 1000 mg every 6-8 hours 4
• NSAIDs if not contraindicated by renal function or surgical considerations 4
• Consider opioid rotation to fentanyl or methadone, which may have less constipating effects 1, 3

Critical Pitfalls to Avoid

Never use PAMORAs in this patient - the combination of diverticulitis history and prior bowel obstruction creates unacceptable perforation risk 2. Even though PAMORAs like naloxegol and naldemedine have strong evidence for laxative-refractory OIC in other populations 1, 3, they are explicitly contraindicated here.

Do not delay prophylactic laxatives - start them simultaneously with opioid initiation, as patients do not develop tolerance to opioid-induced constipation 1, 3.

Avoid stool softeners as monotherapy - docusate alone is ineffective for OIC 3.

Always rule out obstruction before escalating to more aggressive laxative therapy, especially before adding stimulants or enemas in a patient with diverticular disease 1, 4.

Non-Pharmacologic Measures

• Maintain adequate fluid intake (at least 1.5 liters daily) 1, 4
• Increase dietary fiber through fruits, vegetables, and whole grains 4
• Encourage mobility and exercise if feasible 1, 4