What are the guidelines for managing constipation in a general adult population?

Guidelines for Managing Constipation in Adults

Start with polyethylene glycol (PEG) 17g daily as first-line pharmacological therapy after addressing lifestyle factors, and escalate to prescription secretagogues (linaclotide or plecanatide) or the prokinetic prucalopride if symptoms persist after 4-12 weeks. 1, 2

Initial Management Approach

Non-Pharmacological Interventions

• Begin with dietary modifications including increased fluid intake and dietary fiber, along with behavioral changes such as regular exercise and scheduled toileting after meals 1
• These lifestyle modifications represent the initial step before pharmacological intervention 1

Medication Review

• Systematically review all current medications for constipating effects, including antacids, anticholinergic drugs, and antiemetics 3
• Rule out secondary causes including hypothyroidism (TSH testing), hypercalcemia (serum calcium), hypokalemia (basic metabolic panel), and diabetes mellitus 3

Pharmacological Treatment Algorithm

First-Line Therapy: Over-the-Counter Agents

Polyethylene Glycol (PEG)

• PEG receives a strong recommendation as first-line therapy, starting at 17g daily 1, 2
• PEG demonstrates durable response over 6 months with moderate-quality evidence 4
• Common side effects include abdominal distension, loose stool, flatulence, and nausea, which are generally well-tolerated 4
• Continue for 4-12 weeks before considering escalation 4, 3

Fiber Supplementation

• Fiber (polycarbophil, methylcellulose, or psyllium) receives a conditional recommendation as first-line therapy 1, 2
• Increase fiber intake slowly over several weeks to minimize adverse effects such as bloating and gas 5
• Fiber supplementation improves stool consistency and may reduce abdominal pain 6

Second-Line Therapy: Prescription Agents

When to Escalate

• If symptoms do not respond adequately to PEG after 4-12 weeks, escalate to prescription agents rather than continuing to increase osmotic laxative doses 4, 3

Secretagogues (Strong Recommendations)

• Linaclotide 145 mcg once daily receives a strong recommendation for chronic idiopathic constipation 1, 4, 7

  • For IBS-C with significant abdominal pain/bloating, use 290 mcg once daily 7
  • A 72 mcg dose may be used based on individual tolerability 7
  • Take on an empty stomach at least 30 minutes before a meal 7
  • Contraindicated in patients less than 2 years of age due to risk of fatal dehydration 7

• Plecanatide receives a strong recommendation as an alternative secretagogue with similar mechanism to linaclotide 1, 4

Prokinetic Agent (Strong Recommendation)

• Prucalopride (serotonin type 4 agonist) receives a strong recommendation for chronic idiopathic constipation 1, 4
• Prucalopride 2 mg once daily enhances colonic motility through high-amplitude propagated contractions 3
• Consider if secretagogues fail or are not tolerated 4

Alternative and Rescue Therapies

Stimulant Laxatives

• Bisacodyl or sodium picosulfate receive strong recommendations for short-term use (≤4 weeks) or rescue therapy 1, 2, 4

• Can be combined with other pharmacological agents 4

• Sodium picosulfate is contraindicated in patients with congestive heart failure, hypermagnesemia, and severe renal impairment 4

• Elderly patients (≥65 years) on sodium picosulfate have increased risk of hyponatremia (absolute risk increase 0.05%) 4

• Senna receives a conditional recommendation with low-quality evidence 1, 4

• Start with low doses and titrate upward 4

Osmotic Laxatives (Conditional Recommendations)

• Lactulose receives a conditional recommendation 1

• Magnesium oxide receives a conditional recommendation 1

• Magnesium-based products are contraindicated in patients with creatinine clearance <20 mL/min due to risk of hypermagnesemia 4

• Avoid long-term use of magnesium-based laxatives due to potential toxicity 5

Chloride Channel Activator (Conditional Recommendation)

• Lubiprostone receives a conditional recommendation 1, 8
• FDA-approved for chronic idiopathic constipation in adults at standard dosing 8

Agents NOT Recommended

• Discontinue docusate immediately - it provides no therapeutic benefit and is less effective than stimulant laxatives alone 3

Special Considerations

Refractory Constipation

• Confirm adequate trial of current medications for at least 4 weeks before switching 4
• If PEG is inadequate after 4-6 weeks, add or switch to a prescription secretagogue 4
• Perform anorectal testing in patients who do not respond to first-line laxatives to identify defecatory disorders (dyssynergic defecation, pelvic floor dysfunction) 3

Red Flags Requiring Urgent Evaluation

• Rule out mechanical bowel obstruction before escalating laxative therapy, particularly with prominent fecal loading on imaging 3
• Combination of left lower quadrant pain, nausea, and severe constipation warrants consideration of fecal impaction requiring manual disimpaction or glycerin suppositories 3

Fecal Impaction

• Treat with mineral oil or warm water enemas 5

Important Clinical Pitfalls

• Do not continue escalating osmotic laxative doses indefinitely - switch to prescription agents after 4-12 weeks if inadequate response 4, 3
• Avoid magnesium-based laxatives in renal impairment - check creatinine clearance before prescribing 4
• Set realistic expectations - complete symptom resolution is often not achievable, and drug treatment is just one component of multimodal management 3
• Do not use linaclotide in young children - fatal dehydration risk in patients under 2 years 7

Cost and Accessibility Considerations

• PEG is inexpensive, widely available, and well-tolerated, making it the optimal first-line choice 3
• Prescription secretagogues and prokinetics are more expensive but have strong evidence for efficacy when OTC agents fail 4
• The 2023 AGA-ACG guidelines used the GRADE Evidence to Decision framework, which considered costs and health equity in formulating recommendations 1