What medications are recommended for constipation in elderly patients?

Medications for Constipation in Elderly Patients

Polyethylene glycol (PEG) 17g/day is the first-line medication for constipation in elderly patients due to its efficacy and good safety profile. 1

Assessment Considerations

Before initiating medication:

• Evaluate for potential causes:

  • Medication side effects (opioids, anticholinergics, calcium channel blockers)
  • Decreased mobility
  • Inadequate fluid intake
  • Poor dietary habits
  • Underlying medical conditions

• Perform digital rectal examination to assess for:

  • Fecal impaction
  • Rectal tone
  • Presence of masses

Treatment Algorithm

First-Line Treatment

• PEG 3350 (17g/day) 1, 2
  • Dissolve in 4-8 ounces of water, juice, coffee, or tea
  • Excellent safety profile in elderly
  • May take 2-4 days to produce effect
  • Monitor for electrolyte imbalances with prolonged use

Second-Line Options

• Stimulant laxatives (if PEG alone is insufficient)

  • Sennosides or bisacodyl
  • Use with caution due to potential for cramping
  • Can be combined with PEG for more resistant constipation

• Osmotic alternatives

  • Lactulose: 30-45mL (20-30g) three to four times daily 3
  • Adjust dose to produce 2-3 soft stools daily

Third-Line Options

• Rectal measures (for impaction or swallowing difficulties)
  • Suppositories (glycerin)
  • Isotonic saline enemas (preferred over sodium phosphate enemas in elderly) 1

Medications to Avoid or Use with Caution

• Bulk-forming agents (psyllium, methylcellulose)

  • Avoid in non-ambulatory patients with low fluid intake
  • Risk of mechanical obstruction 1, 2

• Saline laxatives (magnesium hydroxide)

  • Use with caution due to risk of hypermagnesemia
  • Avoid in patients with renal insufficiency 1, 2

• Liquid paraffin

  • Avoid in bed-bound patients or those with swallowing disorders
  • Risk of aspiration lipoid pneumonia 1

• Docusate sodium

  • Limited evidence supporting efficacy 4
  • Not recommended as primary treatment

Special Considerations for Opioid-Induced Constipation

• Prophylactic laxative therapy

  • All patients on opioids should receive concomitant laxatives 1, 5
  • Combination of osmotic and stimulant laxatives often needed

• Peripherally acting mu-opioid receptor antagonists (PAMORAs)

  • Consider for refractory opioid-induced constipation
  • Contraindicated in patients with GI obstruction risk 2

Non-Pharmacological Measures

Implement alongside medication therapy:

• Ensure toilet access, especially for patients with decreased mobility
• Optimize toileting habits (attempt defecation 30 minutes after meals)
• Provide dietetic support
• Encourage adequate fluid intake
• Manage decreased food intake that may affect stool consistency

Monitoring and Follow-up

• Reassess within 2-4 weeks of initiating therapy
• Goal: One non-forced bowel movement every 1-2 days
• Monitor for dehydration and electrolyte imbalances, especially in patients with cardiac or renal conditions
• Adjust treatment if diarrhea occurs (reduce dose or discontinue)

Pitfalls to Avoid

• Using bulk laxatives in patients with inadequate fluid intake
• Continuing ineffective treatments without reassessment
• Using docusate as primary therapy despite limited evidence of efficacy
• Failing to provide prophylactic laxatives when prescribing opioids
• Overlooking the need for regular monitoring in patients with cardiac or renal conditions

Remember that constipation management in the elderly requires careful consideration of comorbidities, medication interactions, and functional status, with PEG being the safest and most effective first-line option.