What are the recommendations for the management of constipation?

Management of Constipation

Start with polyethylene glycol (PEG) 17g daily as first-line pharmacological therapy for chronic idiopathic constipation in adults, after considering fiber supplementation for mild cases.

Initial Assessment and Lifestyle Modifications

Begin with a stepwise approach that prioritizes non-pharmacological interventions before escalating to medications:

• Assess total dietary fiber intake before recommending supplementation, as many patients may already consume adequate amounts 1, 2
• Recommend increased fluid intake, particularly for patients consuming less than 500mL/day or those who are elderly, hospitalized, or dehydrated 2, 3
• Encourage regular physical activity (30 minutes daily), though evidence for exercise alone is limited except in specific populations 4, 3

First-Line Pharmacological Treatment

For patients requiring pharmacological intervention, follow this algorithm:

Mild Constipation or First-Step Therapy:

• Fiber supplementation (conditional recommendation): Use psyllium specifically, as it has the best evidence among fiber types 1, 5, 2
• Start with 14g per 1,000 kcal intake daily, ensuring adequate hydration to prevent worsening symptoms 2
• Gradually titrate fiber over several days to minimize flatulence and bloating 1, 3
• Note: Wheat bran and inulin have limited or uncertain efficacy 1

Moderate to Severe Constipation or Fiber Failure:

• Polyethylene glycol (PEG) 17g daily (strong recommendation): This is the preferred first-line pharmacological agent 1, 5, 6
• PEG increases complete spontaneous bowel movements by approximately 2.9 per week compared to placebo 5
• Dissolve in 8 ounces of liquid once daily, taken at approximately the same time each day 5
• Demonstrates durable response over 6 months with common side effects including abdominal distension, loose stool, flatulence, and nausea 5, 2

Second-Line Options

If PEG is insufficient or poorly tolerated, proceed sequentially:

• Osmotic laxatives: Lactulose 15g daily (conditional recommendation) or magnesium oxide 400-500mg daily 5, 2

  • Caution: Avoid magnesium salts in renal impairment due to hypermagnesemia risk 6
  • Lactulose may cause bloating with a 2-3 day latency period 6

• Stimulant laxatives (strong recommendation for sodium picosulfate, conditional for senna): Use when osmotic agents fail 1, 5

  • Goal: One non-forced bowel movement every 1-2 days 2
  • Reserve for PRN use or regular use after first-line failure 7

Third-Line Prescription Agents

For patients unresponsive to over-the-counter options, use prescription secretagogues or prokinetics:

• Linaclotide 145 mcg daily (strong recommendation): FDA-approved for chronic idiopathic constipation in adults; can reduce to 72 mcg based on tolerability 1, 8

  • Take on empty stomach at least 30 minutes before a meal 8
  • Contraindicated in patients less than 2 years of age due to risk of fatal dehydration 8

• Plecanatide (strong recommendation): Alternative guanylate cyclase-C agonist 1, 5

• Prucalopride (strong recommendation): Serotonin type 4 agonist with prokinetic effects 1, 5

• Lubiprostone (conditional recommendation): Chloride channel activator, FDA-approved for chronic idiopathic constipation in adults 1, 9

Special Populations

Opioid-induced constipation:

• Combine PEG with a stimulant laxative (senna or bisacodyl) rather than using docusate 6
• Avoid bulk-forming laxatives like psyllium 6
• Consider methylnaltrexone (peripherally acting μ-opioid antagonist) for persistent symptoms despite laxative therapy 5
• Note: Lubiprostone effectiveness not established for diphenylheptane opioids like methadone 9

Pediatric patients (6-17 years):

• Linaclotide 72 mcg daily is FDA-approved for functional constipation 8

Critical Pitfalls to Avoid

• Do not recommend fiber supplementation without assessing baseline dietary intake 1, 2
• Do not increase fiber without ensuring adequate hydration, as this can worsen constipation 1, 2
• Do not use inadequate trial periods before escalating therapy; allow sufficient time for each intervention 5
• Do not use enemas in neutropenic, thrombocytopenic, or post-colorectal surgery patients 6
• Do not crush or chew linaclotide capsules; swallow whole or open and mix with applesauce/water per specific instructions 8

Cost and Access Considerations

Prioritize treatments based on availability and patient resources:

• Start with generic options (PEG, fiber, lactulose, senna) that are widely available over-the-counter 1
• Prescription agents (linaclotide, plecanatide, prucalopride, lubiprostone) may require prior authorization and have higher out-of-pocket costs 1
• Engage in shared decision-making considering patient preferences, symptom severity, and insurance coverage 1