How to treat constipation?

Management of Constipation

Polyethylene glycol (PEG) at 17g daily is the first-line treatment for constipation due to its efficacy, safety profile, and strong recommendation from clinical guidelines. 1

First-Line Treatment Options

Osmotic Laxatives

• Polyethylene glycol (PEG)

  • Dosage: 17-34g daily mixed in at least 8 ounces of water or other fluid 1, 2
  • Benefits: Highly effective, well-tolerated, safe for most patients 1
  • Caution: Discontinue if diarrhea develops or if abdominal pain worsens 2

• Lactulose

  • Dosage: 15-30ml twice daily 1
  • Note: May cause bloating and flatulence

• Magnesium salts (e.g., milk of magnesia)

  • Contraindication: Avoid in patients with renal impairment due to risk of hypermagnesemia 3, 1

Stimulant Laxatives

• Bisacodyl
  • Dosage: 5-10mg daily 1
  • Best for short-term use or rescue therapy
  • May cause cramping and abdominal discomfort

Treatment Algorithm

1. Start with lifestyle modifications:

   • Increase fluid intake to adequate levels
   • Optimize toileting habits (attempt defecation 30 minutes after meals, twice daily) 1
   • Use proper positioning during bowel movements (a small footstool may help) 1
   • Increase physical activity within patient limits 3

2. First-line pharmacological treatment:

   • PEG 17g daily mixed in 8 oz of fluid 1
   • For new users: Start with one dose per day and gradually increase to three doses daily as necessary 4

3. If inadequate response:

   • Add a stimulant laxative (senna, bisacodyl) 3
   • Preferably administer 30 minutes after a meal to synergize with the gastrocolonic response 3

4. For opioid-induced constipation:

   • Always prescribe a concomitant laxative with opioid therapy unless contraindicated by pre-existing diarrhea 3
   • Avoid bulk laxatives such as psyllium for opioid-induced constipation 3, 1
   • Consider peripherally acting μ-opioid receptor antagonists (PAMORAs) for refractory cases 3, 1

5. For fecal impaction:

   • Confirm with digital rectal examination
   • Use suppositories and enemas as first-line therapy when DRE identifies a full rectum 3
   • Disimpaction through digital fragmentation and extraction of stool, followed by maintenance bowel regimen 3

Special Populations

Elderly Patients

• Pay particular attention to assessment of elderly patients 3
• Ensure access to toilets, especially with decreased mobility 3
• Provide dietetic support 3
• PEG (17 g/day) offers an efficacious and tolerable solution with good safety profile 3
• Avoid liquid paraffin for bed-bound patients and those with swallowing disorders 3
• Use isotonic saline enemas rather than sodium phosphate enemas in older adults 3

Pregnant Patients

• First-line: increase fiber, fluids, and exercise
• If ineffective, consider bulk-forming agents, lubricant laxatives, stool softeners
• Use osmotic and stimulant laxatives only short-term to avoid dehydration or electrolyte imbalances 5

Monitoring and Red Flags

• Monitor for red flags: severe abdominal pain, no bowel movement for >3 days, vomiting, signs of bowel obstruction 1
• Weekly monitoring of bowel movement frequency and consistency 1
• Discontinue laxative use and consult a doctor if rectal bleeding occurs or if nausea, bloating, cramping, or abdominal pain worsens 2

Contraindications and Precautions

• Avoid enemas in patients with neutropenia, thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal or gynecological surgery, severe colitis, inflammation or infection, toxic megacolon, undiagnosed abdominal pain, or recent pelvic radiotherapy 3, 1
• Avoid bulk laxatives in non-ambulatory patients with low fluid intake due to risk of mechanical obstruction 3
• Contrary to common belief, stimulant laxatives at recommended doses are not harmful to the colon and do not cause dependency 6