What is the recommended regimen for managing constipation?

Management of Constipation

Polyethylene glycol (PEG) is recommended as first-line pharmacological treatment for constipation, with a standard dose of 17g dissolved in 4-8 ounces of beverage once daily. 1

Initial Assessment and Classification

• Constipation is defined by symptoms including:

  • Infrequent bowel movements (less than 3 per week)
  • Hard stools
  • Straining during defecation
  • Sensation of incomplete evacuation
  • Need for manual maneuvers during defecation

• Digital rectal examination should be performed to assess for fecal impaction, which would require disimpaction before maintenance therapy 2

Step-by-Step Management Algorithm

Step 1: Lifestyle Modifications (as adjuncts to pharmacological treatment)

• Increase fluid intake and physical activity 1
• Gradually increase dietary fiber to 20-25g per day, focusing on soluble fiber 1
• Optimize toileting habits:
  • Ensure privacy and comfort for defecation
  • Use a footstool to elevate knees above hips
  • Attempt defecation at least twice a day, usually 30 minutes after meals
  • Strain no more than 5 minutes 2, 1

Step 2: First-line Pharmacological Treatment

• Osmotic Laxatives (preferred first-line option):
  • Polyethylene glycol (PEG) 17g/day dissolved in at least 8 oz of fluid 2, 1
  • Alternatives: lactulose or magnesium salts (use magnesium salts cautiously in renal impairment) 2

Step 3: If Inadequate Response to Osmotic Laxatives

• Add Stimulant Laxatives:
  • Senna, bisacodyl, cascara, or sodium picosulfate 2, 1
  • These increase intestinal motility but may cause abdominal cramping

Step 4: For Opioid-Induced Constipation

• Prophylactically prescribe laxatives when initiating opioid therapy 1
• Increase laxative dose when increasing opioid dose 1
• Consider peripherally acting mu-opioid receptor antagonists (PAMORAs) for unresolved OIC, but not as first-line treatment 2, 1

Step 5: For Rectal Loading or Fecal Impaction

• Use suppositories and enemas as first-line therapy when digital rectal examination identifies a full rectum or fecal impaction 2
• Isotonic saline enemas are preferable in older adults 2
• Contraindications for enemas: neutropenia, thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal surgery, severe colitis, undiagnosed abdominal pain 2

Special Considerations

Elderly Patients

• Ensure access to toilets, especially with decreased mobility 2
• Provide dietetic support 2
• PEG (17 g/day) offers an efficacious and tolerable solution 2
• Avoid liquid paraffin for bed-bound patients and those with swallowing disorders 2
• Use saline laxatives cautiously due to risk of hypermagnesemia 2

Specific Agents to Avoid or Use Cautiously

• Bulk-forming laxatives (psyllium, methylcellulose):

  • Not recommended for opioid-induced constipation 2
  • May worsen constipation in many cases 1
  • Avoid in non-ambulatory patients with low fluid intake due to risk of mechanical obstruction 2
  • If using psyllium, start with 1 packet in 8 oz of liquid daily, gradually increasing to 3 times daily as needed 3

• Stool softeners (docusate sodium):

  • Limited evidence of benefit 1
  • Generally produces bowel movement in 12-72 hours 4

Monitoring and Follow-up

• Reassess treatment efficacy within 2-4 weeks of initiating treatment 1
• Adjust the plan as needed based on response 1
• Evaluate for fecal impaction if symptoms persist despite treatment 1

Common Pitfalls to Avoid

• Relying solely on lifestyle modifications without appropriate pharmacological intervention 1
• Using fiber supplements in patients with suspected obstruction 1
• Continuing ineffective treatments without reassessment 1
• Failing to prophylactically treat constipation when prescribing opioids 1
• Using oral laxatives containing sodium phosphate in patients at risk for renal dysfunction 1