What are the treatment options for constipation?

Treatment Options for Constipation

Polyethylene glycol (PEG) is the first-line pharmacological treatment for chronic constipation, with a strong recommendation and moderate certainty of evidence, increasing complete spontaneous bowel movements by approximately 2.9 per week. 1

Initial Treatment Approach

First-Line Options

1. Lifestyle modifications:

   • Optimize toileting habits: attempt defecation 30 minutes after meals, strain no more than 5 minutes 1
   • Increase fluid intake and encourage physical activity 1
   • Maintain adequate dietary fiber intake (though fiber supplements like Metamucil are unlikely to control opioid-induced constipation) 1

2. Pharmacological treatment:

   • Polyethylene glycol (PEG): 17-34g daily 1
     • Most studied laxative with best results and fewest side effects 2
     • Forms an isotonic solution that increases intestinal content volume 2

Alternative First-Line Options

• Lactulose: 15-30ml twice daily 1
• Magnesium hydroxide: Alternative to PEG (avoid in renal impairment) 1
• Bisacodyl: 10-15mg daily (for short-term or rescue therapy) 1

Specific Treatment for Different Types of Constipation

For Opioid-Induced Constipation (OIC)

1. Preventive approach:

   • Start prophylactic laxative regimen when initiating opioid therapy 1
   • Use stimulant laxatives (particularly senna) as first-line agents 1

2. For persistent OIC despite laxative therapy:

   • Peripherally acting μ-opioid receptor antagonists (PAMORAs):
     • Naldemedine: 0.2mg daily (strong recommendation, high-quality evidence) 1
     • Naloxegol: 25mg once daily (strong recommendation, moderate-quality evidence) 1
     • Methylnaltrexone: 0.15mg/kg subcutaneously every other day (conditional recommendation) 1

For Irritable Bowel Syndrome with Constipation (IBS-C)

• Linaclotide: FDA-approved for IBS-C in adults 3
  • Improves abdominal pain, stool consistency, and complete spontaneous bowel movements 3
  • Effects typically begin within 1 week of treatment 3

Treatment Algorithm Based on Response

1. Start with PEG (17-34g daily)

2. If inadequate response after 1-2 weeks:

   • Add or switch to stimulant laxative (bisacodyl 10-15mg daily)
   • Consider combination therapy with soluble fiber (psyllium) and PEG 2

3. If still inadequate:

   • For OIC: Add PAMORA
   • For chronic idiopathic constipation: Consider linaclotide 3
   • Perform anorectal testing to identify defecatory disorders 1

4. For refractory cases:

   • Consider surgical options (only in ~5% of cases) such as total colectomy with ileorectal anastomosis for documented slow transit constipation 1

Important Precautions and Contraindications

• Avoid magnesium-containing laxatives in elderly patients or those with renal impairment (risk of hypermagnesemia) 1
• Avoid lactulose in patients with neutropenia, thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal surgery, or severe colitis 1
• Avoid liquid paraffin in bed-bound patients (risk of aspiration) 1
• Avoid bulk laxatives for opioid-induced constipation 1
• Docusate is ineffective for constipation management in adults 1

Monitoring and Follow-up

• Goal of therapy: achieve one non-forced bowel movement every 1-2 days 1
• Monitor for red flags: severe abdominal pain, no bowel movement for >3 days, vomiting, signs of bowel obstruction 1
• Weekly monitoring of bowel movement frequency and consistency, severity of muscle spasms, mental status 1

Special Considerations

• Elderly patients require particular attention to medication lists and comorbidities, as they are at higher risk for severe constipation and impaction 1
• For swallowing difficulties, consider rectal measures (suppositories, enemas) 1
• Lactulose enema can be used as an alternative to oral laxatives (300 mL lactulose mixed with 700 mL water/saline) 1