What are the treatment options for long-term constipation?

Long-Term Constipation Treatment

Polyethylene glycol (PEG) is the first-line pharmacological treatment for chronic constipation due to its strong evidence base, with fiber supplementation recommended as an initial or complementary approach for milder cases. 1, 2

First-Line Approach

Lifestyle Modifications

• Optimize toileting habits: attempt defecation 30 minutes after meals
• Strain no more than 5 minutes
• Increase fluid intake (especially for those with low fluid consumption)
• Encourage physical activity when appropriate

Dietary Interventions

• Fiber supplementation:
  • Psyllium: 15g daily (preferred fiber supplement) 2
  • Gradually increase fiber intake to avoid bloating and flatulence
  • Target at least 20-25g of fiber daily 3
  • Note: Bulk laxatives like fiber are less effective for opioid-induced constipation 2

First-Line Pharmacological Treatment

• Polyethylene glycol (PEG): 17g daily, mixed in 8 ounces of liquid 1, 2
  • Strong recommendation with moderate certainty of evidence
  • Increases complete spontaneous bowel movements by approximately 2.9 per week 1
  • Response is durable over at least 6 months
  • Side effects: abdominal distension, loose stool, flatulence, nausea

Second-Line Treatments

Osmotic Laxatives

• Lactulose: 15-30ml twice daily 2
• Magnesium hydroxide (Milk of Magnesia): 1 oz twice daily 2
  • Avoid in elderly patients and those with renal impairment

Stimulant Laxatives

• Bisacodyl: 10-15mg daily 1, 2
• Senna: Particularly effective for opioid-induced constipation 2
• Glycerol suppositories: Preferably administered 30 minutes after meals 2

Specialized Treatments for Specific Conditions

For Defecatory Disorders

• Biofeedback therapy: Strongly recommended over laxatives with high-quality evidence 2
  • Success rate >70% improvement in symptoms
  • Particularly effective for dyssynergic defecation

For Opioid-Induced Constipation (OIC)

1. Preventive approach: Start prophylactic laxative regimen when initiating opioid therapy 2
2. First-line treatment: Stimulant laxatives (particularly senna) or PEG 2
3. For refractory OIC: Consider peripherally acting μ-opioid receptor antagonists (PAMORAs)
   • Methylnaltrexone: 0.15mg/kg subcutaneously every other day 1, 2
   • Naldemedine: 0.2mg daily 2
   • Naloxegol: 25mg once daily 2

For Irritable Bowel Syndrome with Constipation (IBS-C)

• Lubiprostone: FDA-approved for IBS-C in women ≥18 years 4
• Linaclotide: Effective for IBS-C, improves abdominal pain and CSBM frequency 5

Treatment Algorithm for Chronic Constipation

1. Mild constipation:

   • Start with fiber supplementation (psyllium 15g daily)
   • Ensure adequate fluid intake
   • Optimize toileting habits

2. Moderate constipation or inadequate response to fiber:

   • Add PEG 17g daily
   • Can be used in combination with fiber

3. Inadequate response to PEG:

   • Add or switch to stimulant laxative (bisacodyl 10-15mg daily)
   • Consider adding osmotic laxatives like lactulose

4. Refractory constipation:

   • Evaluate for defecatory disorders with anorectal testing 2
   • Consider prescription medications:
     • Lubiprostone for chronic idiopathic constipation 4
     • Linaclotide for IBS-C 5

5. Opioid-induced constipation:

   • Start with stimulant laxatives and PEG
   • For refractory cases, add PAMORAs

Important Cautions and Monitoring

• Avoid docusate as it is ineffective for constipation management 2
• Avoid saline laxatives in elderly patients or those with renal impairment 2
• Don't use enemas in patients with neutropenia, thrombocytopenia, recent colorectal surgery, or severe colitis 2
• Monitor for treatment goal: one non-forced bowel movement every 1-2 days 2
• Watch for red flags: severe abdominal pain, no bowel movement for >3 days, vomiting, and signs of bowel obstruction 2

Surgery (e.g., total colectomy with ileorectal anastomosis) should be reserved only for documented slow transit constipation that has failed all other treatments, applicable in approximately 5% of cases 2, 6.