What are the treatment options for constipation?

Treatment Options for Constipation

The first-line treatment for constipation should include stimulant laxatives such as bisacodyl 10-15 mg 2-3 times daily or senna, with a goal of one non-forced bowel movement every 1-2 days. 1, 2

Initial Assessment and Management

• Rule out treatable causes of constipation including impaction, obstruction, hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 1, 2
• Physical examination should include abdominal exam and digital rectal examination to assess for impaction 2
• Lifestyle modifications should be implemented:
  • Increased fluid intake 1, 3
  • Increased physical activity when appropriate 1, 3
  • Added dietary fiber (25g/day) for patients with adequate fluid intake 1, 3

First-Line Pharmacological Treatment

• Stimulant laxatives are recommended as first-line therapy:
  • Bisacodyl 10-15 mg, 2-3 times daily 1, 2
  • Senna (evidence shows senna alone is more effective than combined with docusate) 1, 2
• If impaction is observed:
  • Administer glycerine suppositories 1
  • Consider manual disimpaction if necessary 1

Second-Line Treatment Options

For persistent constipation, consider adding:

• Osmotic laxatives:
  • Polyethylene glycol (PEG) 1, 2, 4
  • Lactulose 1
  • Magnesium hydroxide or magnesium citrate (use cautiously in renal impairment) 1
• Rectal bisacodyl suppositories once daily 1, 2
• If gastroparesis is suspected, add a prokinetic agent such as metoclopramide 1

Management of Opioid-Induced Constipation (OIC)

• Prophylactic bowel regimen is essential as patients do not develop tolerance to this adverse effect 1
• For OIC that doesn't respond to standard laxative therapy:
  • Peripherally acting μ-opioid receptor antagonists:
    • Methylnaltrexone 0.15 mg/kg every other day (no more than once daily) 1, 2
    • Naloxegol for patients receiving chronic opioids 1
  • Avoid methylnaltrexone in patients with postoperative ileus or mechanical bowel obstruction 1

Advanced Treatment Options for Refractory Constipation

• Intestinal secretagogues:
  • Lubiprostone (prostaglandin analog that activates chloride channels) 1, 4
  • Linaclotide (guanylate cyclase-C receptor agonist) - FDA approved for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) 1, 5
• Consider combination therapy with peripherally acting μ-opioid receptor antagonists and secretagogues for severe cases 1

Common Pitfalls to Avoid

• Using stool softeners alone without stimulant laxatives is ineffective 1, 2
• Failing to provide prophylactic treatment when starting constipating medications 1, 2
• Supplemental medicinal fiber (like psyllium) is ineffective for opioid-induced constipation 1
• Magnesium-based products should be used cautiously in patients with renal impairment 1, 2
• Enemas should be avoided in patients with neutropenia or thrombocytopenia 2

Treatment Algorithm Based on Constipation Severity

1. Mild constipation:

   • Lifestyle modifications (fluid, fiber, exercise) 1, 3
   • Stimulant laxatives as needed 1

2. Moderate constipation:

   • Scheduled stimulant laxatives 1
   • Add osmotic laxatives if response is inadequate 1, 4

3. Severe or refractory constipation:

   • Combination of stimulant and osmotic laxatives 1
   • Consider adding secretagogues (lubiprostone, linaclotide) 1, 5
   • For OIC, add peripherally acting μ-opioid receptor antagonists 1, 6

4. Impaction:

   • Suppositories, enemas, or manual disimpaction 1
   • Aggressive oral regimen after disimpaction to prevent recurrence 1, 2