What are the recommended medications and treatments for constipation?

Recommended Medications and Treatments for Constipation

For most patients with constipation, a stepwise approach starting with osmotic laxatives such as polyethylene glycol (PEG) or stimulant laxatives is recommended as first-line pharmacological therapy, with fiber supplementation as an adjunctive treatment. 1

First-Line Treatments

Non-Pharmacological Approaches

• Ensure adequate hydration and increase fluid intake 1
• Increase physical activity and mobility within patient limits 1
• Optimize toileting position (using a footstool can help) and ensure privacy 1
• Establish regular toileting habits, attempting defecation 30 minutes after meals 1
• Consider abdominal massage, particularly for patients with neurogenic problems 1

Fiber Supplementation

• Recommended initial dose: 14g/1,000 kcal intake per day 1
• Psyllium appears to be the most effective fiber supplement compared to other types 1, 2
• Ensure adequate hydration when increasing fiber intake 1
• Common side effects include bloating and abdominal discomfort 1
• Not recommended for opioid-induced constipation 1

Pharmacological Treatments

Osmotic Laxatives (First-Line)

• Polyethylene glycol (PEG): 17g daily; no clear maximum dose; $10-$45 monthly 1
  • Response has been shown to be durable over 6 months 1
  • Side effects include bloating, abdominal discomfort, and cramping 1
• Lactulose: 15g daily; no clear maximum dose; <$50 monthly 1
  • Only osmotic agent studied in pregnancy 1
  • May cause bloating and flatulence, especially at higher doses 1
• Magnesium oxide: 400-500mg daily; no clear maximum dose; <$50 monthly 1
  • Use with caution in patients with renal insufficiency 1

Stimulant Laxatives (First-Line)

• Bisacodyl: 5mg daily initially; maximum 10mg daily; <$50 monthly 1
  • Recommended for short-term use or rescue therapy 1
  • Side effects include cramping and abdominal discomfort 1
• Senna: 8.6-17.2mg daily; no clear maximum dose; <$50 monthly 1
  • Also present in many laxative teas 1
  • Recommended maximum is 4 tablets twice per day 1

Second-Line Treatments (Prescription)

Intestinal Secretagogues

• Lubiprostone: 24μg twice daily; $374 monthly 1
  • May have benefit for abdominal pain 1
  • Diarrhea may occur in some patients 1
• Linaclotide: 72-145μg daily for chronic idiopathic constipation; maximum 290μg daily; $523 monthly 1, 3
  • Take on empty stomach at least 30 minutes prior to meals 3
  • May have benefit for abdominal pain 1
• Plecanatide: 3mg daily; $526 monthly 1
  • Diarrhea may occur in some patients 1
• Prucalopride: 1-2mg daily; $563 monthly 1
  • May have additional benefit for abdominal pain 1
  • Headaches and diarrhea may occur 1

Special Considerations

Opioid-Induced Constipation (OIC)

• All patients receiving opioid analgesics should be prescribed a concomitant laxative unless contraindicated 1
• Osmotic or stimulant laxatives are generally preferred 1
• For unresolved OIC, consider peripherally acting μ-opioid receptor antagonists (PAMORAs) such as methylnaltrexone (0.15 mg/kg subcutaneously) 1
• Bulk laxatives such as psyllium are not recommended for OIC 1

Fecal Impaction

• Digital disimpaction followed by maintenance bowel regimen is recommended 1
• Suppositories and enemas are preferred first-line therapy when digital rectal examination identifies a full rectum or fecal impaction 1

Elderly Patients

• Ensure access to toilets, especially for those with decreased mobility 1
• Provide dietetic support 1
• Optimize toileting habits (attempt defecation twice daily, 30 minutes after meals) 1
• Polyethylene glycol (17g/day) offers an efficacious and tolerable solution with good safety profile 1
• Avoid liquid paraffin for bed-bound patients and those with swallowing disorders due to risk of aspiration 1

Treatment Algorithm

1. Start with non-pharmacological approaches and fiber supplementation (if not OIC) 1
2. If inadequate response, add osmotic laxative (PEG preferred) 1, 4
3. If still inadequate, add or switch to stimulant laxative 1
4. For persistent symptoms, consider prescription medications (secretagogues) 1
5. For OIC, use osmotic or stimulant laxatives first, then consider PAMORAs if refractory 1

Common Pitfalls

• Not all fiber supplements are equally effective; psyllium has better evidence than other types 1, 2
• Inadequate fluid intake when increasing fiber can worsen constipation 1
• Using bulk-forming laxatives in opioid-induced constipation 1
• Failure to recognize and treat fecal impaction before starting a maintenance regimen 1
• Not adjusting laxative doses when increasing opioid doses 1
• Using magnesium salts in patients with renal impairment 1