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

Initial Assessment and Management

• Assess for potential causes of constipation including medications, hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 1, 2
• Perform physical examination including digital rectal examination to rule out impaction 2
• Encourage lifestyle modifications including:
  • Increased fluid intake 1
  • Increased physical activity when appropriate 1
  • Added dietary fiber (25g/day) for patients with adequate fluid intake 1

First-Line Pharmacological Treatment

• Stimulant laxatives are recommended as first-line therapy:
  • Bisacodyl 10-15 mg, 2-3 times daily 1
  • Senna (evidence shows senna alone is more effective than combined with docusate) 1, 2
• Goal of treatment: one non-forced bowel movement every 1-2 days 1
• If impaction is observed:
  • Administer glycerine suppositories 1
  • Perform manual disimpaction if necessary 1

Second-Line Treatment for Persistent Constipation

• Add osmotic laxatives if constipation persists:
  • Polyethylene glycol (PEG) - 17g with 8 oz water twice daily 1, 2
  • Lactulose 1
  • Magnesium hydroxide or magnesium citrate (use cautiously in renal impairment) 1
• Consider rectal bisacodyl once daily 1
• If gastroparesis is suspected, add a prokinetic agent such as metoclopramide 1

Management of Opioid-Induced Constipation

• For opioid-induced constipation that has not responded to standard laxative therapy:
  • Methylnaltrexone 0.15 mg per kilogram of body weight every other day (no more than once daily) 1
  • Do not use methylnaltrexone in patients with postoperative ileus or mechanical bowel obstruction 1
• Other peripherally acting μ-opioid receptor antagonists:
  • Naloxegol for patients receiving chronic opioids for non-cancer pain 1

Advanced Treatment Options for Refractory Constipation

• For constipation associated with irritable bowel syndrome or chronic idiopathic constipation:
  • Lubiprostone (activates chloride channels to enhance intestinal fluid secretion) 1, 3
  • Linaclotide (selective agonist of guanylate cyclase-C receptors that enhances intestinal secretions) 1, 3
• For severe refractory cases, gastrointestinal specialists have reported some success using erythromycin 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 (especially opioids) 1
• Bulk laxatives are not recommended for opioid-induced constipation 1
• Magnesium-based products should be used cautiously in patients with renal impairment 1, 2
• Methylnaltrexone should not be used in patients with bowel obstruction 1

Treatment Algorithm

1. Start with lifestyle modifications + stimulant laxative (bisacodyl or senna)
2. If inadequate response, add osmotic laxative (PEG, lactulose, or magnesium salts)
3. For persistent symptoms, add rectal treatments (suppositories) or prokinetic agents
4. For opioid-induced constipation unresponsive to above measures, add peripherally acting μ-opioid receptor antagonist
5. For refractory cases, consider secretagogues (lubiprostone or linaclotide) or specialist referral 1, 2