What is the best approach for managing treatment-resistant constipation in the elderly?

Management of Treatment-Resistant Constipation in the Elderly

Polyethylene glycol (PEG) at 17 g/day is the most effective first-line pharmacological treatment for treatment-resistant constipation in elderly patients due to its efficacy and excellent safety profile. 1

Initial Assessment and Non-Pharmacological Approaches

Before escalating to more aggressive pharmacological treatments, ensure these foundational measures are optimized:

• Ensure adequate toilet access, especially for patients with decreased mobility 2
• Provide dietetic support to address nutritional factors contributing to constipation 2
• Address decreased food intake related to aging (anorexia of aging, chewing difficulties) which negatively influence stool volume and consistency 2
• Optimize toileting habits by educating patients to attempt defecation twice daily, usually 30 minutes after meals, and to strain no more than 5 minutes 2, 1
• Regular monitoring of chronic kidney/heart failure when patients are on concomitant treatment with diuretics or cardiac glycosides due to risk of dehydration and electrolyte imbalances 2

Pharmacological Management Algorithm

1. First-line: Polyethylene glycol (PEG)

   • Start with PEG 17 g/day as the primary treatment option 1
   • PEG offers an efficacious and tolerable solution with good safety profile specifically for elderly patients 2
   • Does not require increased fluid intake like bulk-forming laxatives 3

2. Second-line: Osmotic alternatives

   • If PEG is not tolerated, consider other osmotic laxatives like lactulose 1, 4
   • Avoid magnesium-based osmotic laxatives due to risk of hypermagnesemia in elderly patients, particularly those with renal impairment 2

3. Third-line: Stimulant laxatives

   • Consider stimulant laxatives (senna, bisacodyl) if osmotic agents are ineffective 1, 4
   • Use with caution due to risk of pain and cramps 2
   • Best used intermittently rather than continuously 3

4. Fourth-line: Secretagogues

   • For truly treatment-resistant cases, consider lubiprostone 24 mcg twice daily 5
   • Lubiprostone has demonstrated efficacy in elderly patients with chronic idiopathic constipation 5
   • Note that elderly patients taking lubiprostone experienced a lower rate of associated nausea compared to the overall population (19% vs. 29%) 5

Special Considerations and Cautions

• Avoid bulk-forming laxatives in non-ambulatory elderly patients with low fluid intake due to increased risk of mechanical obstruction 2
• Avoid liquid paraffin for bed-bound patients and those with swallowing disorders due to risk of aspiration lipoid pneumonia 2
• For recurrent fecal impaction or swallowing difficulties, rectal measures (suppositories or enemas) may be the preferred choice 2, 1
  • Use isotonic saline enemas rather than sodium phosphate enemas due to safety concerns in elderly patients 2
• Adjust dosing for hepatic impairment: For medications like lubiprostone, dosage adjustment is needed for patients with moderate to severe hepatic impairment 5

Management of Complications

• For fecal impaction: In the absence of suspected perforation or bleeding, perform disimpaction (usually through digital fragmentation and extraction), followed by implementation of a maintenance bowel regimen to prevent recurrence 2
• For opioid-induced constipation: Consider peripherally acting mu-opioid receptor antagonists (PAMORAs) if other treatments fail, though these can be expensive 2, 4

Monitoring Response

• Regularly assess bowel movement frequency, stool consistency, and straining 5
• Monitor for adverse effects, particularly in patients with renal impairment 1
• If no improvement after sequential trials of the above treatments, consider referral for further diagnostic evaluation to rule out underlying pathology 4, 6