What is the treatment for severe constipation?

Treatment for Severe Constipation

For severe constipation, treatment should begin with osmotic or stimulant laxatives, with polyethylene glycol (PEG) or bisacodyl being first-line options, followed by escalation to combination therapy or peripherally acting μ-opioid receptor antagonists for refractory cases. 1

Initial Assessment

Before initiating treatment, assess:

• Potential causes: medications (especially opioids), metabolic disorders (hypercalcemia, hypokalemia, hypothyroidism, diabetes)
• Rule out impaction, obstruction through physical examination
• Severity of symptoms and impact on quality of life

Treatment Algorithm

Step 1: Non-pharmacological Interventions

• Increase fluid intake (especially important when increasing fiber)
• Encourage physical activity when appropriate
• Consider dietary modifications:
  • Added dietary fiber only for patients with adequate fluid intake
  • Goal of 20-25g fiber daily, introduced gradually 2

Step 2: First-Line Pharmacological Treatment

• Osmotic laxatives:

  • Polyethylene glycol (PEG): One capful with 8oz water twice daily 1
  • Alternatives: lactulose, magnesium hydroxide, magnesium citrate

• Stimulant laxatives:

  • Bisacodyl 10-15mg, 2-3 times daily 1
  • Alternatives: senna, sodium picosulfate
  • Goal: one non-forced bowel movement every 1-2 days

Note: Evidence suggests stimulant laxatives alone may be more effective than combinations with stool softeners like docusate 1

Step 3: For Impaction

• If impaction is present:
  • Glycerin suppositories
  • Manual disimpaction if necessary
  • Followed by enemas (unless contraindicated)
  • Then implement maintenance regimen to prevent recurrence 1

Step 4: For Persistent Constipation

• Add additional laxatives:

  • Rectal bisacodyl once daily
  • Increase oral osmotic laxatives
  • Consider combination therapy of different mechanisms

• For gastroparesis-related constipation:

  • Add metoclopramide (use with caution due to risk of tardive dyskinesia with chronic use) 1

Step 5: For Refractory Constipation

• For opioid-induced constipation unresponsive to standard therapy:

  • Methylnaltrexone 0.15mg/kg every other day (not more than once daily) 1
  • Alternative: naloxegol
  • Contraindicated in patients with postoperative ileus or mechanical bowel obstruction 1

• Consider newer agents for specific indications:

  • Linaclotide for chronic idiopathic constipation or IBS-C 1, 3
  • Lubiprostone for opioid-induced constipation in chronic non-cancer pain 1

Special Considerations

Opioid-Induced Constipation

• Prophylactic treatment with stimulant laxatives is recommended when starting opioid therapy 1
• Bulk laxatives like psyllium are NOT recommended for opioid-induced constipation 1
• Consider opioid rotation to fentanyl or methadone if constipation persists 1

Elderly Patients

• At higher risk for constipation (24-50% prevalence)
• May require more aggressive management due to degenerative changes in enteric nervous system 1
• Ensure adequate hydration, particularly important in this population

Pitfalls to Avoid

1. Overreliance on fiber supplements alone for severe constipation, especially in opioid-induced cases
2. Using bulk-forming agents without adequate fluid intake, which can worsen constipation
3. Failing to identify and address underlying causes (medications, metabolic disorders)
4. Delaying treatment escalation when first-line therapies fail
5. Using enemas in contraindicated conditions (neutropenia, thrombocytopenia, recent colorectal surgery, severe colitis) 1

Remember that severe constipation requires prompt and effective management to prevent complications such as impaction, bowel obstruction, and significant deterioration in quality of life.