What is the treatment for severe constipation in adults?

Treatment of Severe Constipation in Adults

For severe constipation in adults, a stepped approach beginning with polyethylene glycol (PEG) as first-line therapy is strongly recommended, followed by stimulant laxatives, and progressing to prescription medications like linaclotide, plecanatide, or prucalopride if initial treatments fail. 1

Initial Management

First-Line Treatment

• Polyethylene glycol (PEG): Strong recommendation with moderate certainty of evidence 1
  • Dosage: 17g dissolved in 8 ounces of water once or twice daily
  • Mechanism: Increases water content in the bowel by sequestering fluid
  • Benefits: Increases complete spontaneous bowel movements (CSBMs) by approximately 2.9 per week compared to placebo 1
  • Side effects: Abdominal distension, loose stool, flatulence, and nausea

Concurrent Lifestyle Modifications

• Increase dietary fiber intake to 20-30g daily
• Ensure adequate fluid intake (at least 1.5-2L daily)
• Regular physical activity
• Establish regular toileting habits

Second-Line Treatments

Osmotic Laxatives

• Lactulose: 15-30mL daily or twice daily

  • Produces osmotic diarrhea of low pH
  • May cause bloating and flatulence 1

• Magnesium salts: Useful for rapid bowel evacuation

  • Avoid in renal impairment
  • Avoid sodium salts due to risk of sodium/water retention 1

Stimulant Laxatives

• Bisacodyl: 5-10mg orally or as suppository

  • Strong recommendation with moderate certainty 1
  • Stimulates sensory nerves in proximal colon

• Sodium picosulfate: Strong recommendation 1

  • Similar mechanism to bisacodyl

• Senna: Conditional recommendation 1

  • Acts by stimulating myenteric plexus in colon
  • Contrary to previous belief, no evidence of damage to intestinal muscle with prolonged use 1

Third-Line Treatments (For Refractory Constipation)

Secretagogues

• Linaclotide: 145mcg daily for chronic idiopathic constipation 2

  • Strong recommendation 1
  • Mechanism: Increases intestinal fluid secretion
  • Efficacy: Significantly increases CSBMs compared to placebo
  • FDA approved for chronic idiopathic constipation

• Plecanatide: Strong recommendation 1

  • Similar mechanism to linaclotide

• Lubiprostone: 24mcg twice daily 3

  • Conditional recommendation 1
  • FDA approved for chronic idiopathic constipation

Prokinetic Agents

• Prucalopride: Strong recommendation 1
  • 5-HT4 receptor agonist with prokinetic properties
  • Does not have the cardiac risks associated with older agents like cisapride 1
  • Side effects: Headache and gastrointestinal symptoms

Special Considerations

Opioid-Induced Constipation

• Consider peripherally acting mu-opioid receptor antagonists:
  • Methylnaltrexone (subcutaneous)
  • Naloxegol (oral)
  • Naldemedine (oral) 1

Refractory Cases

• Combination therapy: Consider combining agents with different mechanisms of action

  • Example: PEG plus a stimulant laxative 1

• Specialized testing: If constipation persists despite adequate trials of multiple agents, consider:

  • Colonic transit studies
  • Anorectal manometry
  • Defecography to rule out pelvic floor dysfunction

Important Caveats

1. Rule out obstruction: Always assess for potential bowel obstruction before initiating stimulant laxatives 1

2. Medication review: Evaluate and modify medications that may contribute to constipation

3. Docusate ineffective: Based on available literature, docusate has not shown benefit and is not recommended 1

4. Fiber caution: While dietary fiber is beneficial, supplemental medicinal fiber may worsen severe constipation 1

5. Avoid sodium phosphate: Limit sodium phosphate laxatives to once daily in patients at risk for renal dysfunction 1