What are the guidelines for managing constipation?

Management of Constipation: Evidence-Based Guidelines

Start with osmotic laxatives (polyethylene glycol 17g daily) or stimulant laxatives (senna, bisacodyl) as first-line pharmacological therapy, combined with non-pharmacological measures including adequate hydration, increased mobility, and proper toileting habits. 1, 2

Initial Assessment

All patients should be systematically evaluated for constipation with focused questioning about stool frequency, consistency, straining, and sense of incomplete evacuation. 1

Physical examination must include:

• Abdominal examination to assess for distension, masses, or fecal loading 1
• Perineal inspection for anatomic abnormalities 1
• Digital rectal examination (DRE) to identify rectal impaction or pelvic floor dysfunction 1

Laboratory investigations are not routinely necessary but should include corrected calcium and thyroid function if clinically suspected, particularly in elderly patients or those with sudden symptom changes. 1 Plain abdominal X-ray may help visualize fecal loading extent and exclude bowel obstruction. 1

Non-Pharmacological Management (First-Line for All Patients)

Environmental and behavioral modifications:

• Ensure privacy and comfort during defecation 1, 2
• Use a small footstool to assist gravity and facilitate proper positioning 1, 2
• Establish regular toileting attempts twice daily, ideally 30 minutes after meals, straining no more than 5 minutes 1, 3
• Increase fluid intake to at least 1.5 liters daily 2, 3
• Increase physical activity and mobility within patient limits (even bed-to-chair transfers help) 1, 2

Dietary fiber supplementation:

• Target 14g fiber per 1,000 kcal intake daily (approximately 20-25g total daily) 2, 4
• Titrate gradually over several days to minimize bloating and abdominal discomfort 2, 4
• Critical caveat: Adequate hydration is essential when increasing fiber; insufficient fluid intake worsens constipation 2, 3

Abdominal massage may reduce gastrointestinal symptoms and improve bowel efficiency, particularly in patients with neurogenic problems. 1

Pharmacological Management

First-Line Laxatives

Osmotic laxatives (preferred):

• Polyethylene glycol (PEG) 17g daily is the gold standard with excellent efficacy and safety profile, particularly in elderly patients 1, 2, 3, 5
• Lactulose 15-30 mL daily (causes more bloating/flatulence but is the only osmotic agent studied in pregnancy) 2, 3
• Magnesium salts 400-500mg daily—use cautiously in renal impairment due to hypermagnesemia risk 1, 2

Stimulant laxatives (equally acceptable first-line):

• Senna 8.6-17.2mg daily 1, 2
• Bisacodyl 5-10mg daily 1, 2
• Sodium picosulfate 1
• Important limitation: Reserve primarily for short-term use or rescue therapy due to potential cramping, abdominal discomfort, and electrolyte imbalance with prolonged use 2

Agents to avoid:

• Bulk laxatives (psyllium) are NOT recommended for opioid-induced constipation and should be avoided in non-ambulatory patients with low fluid intake due to mechanical obstruction risk 1, 2, 3
• Docusate sodium has inadequate experimental evidence and is ineffective 1, 3
• Liquid paraffin should be avoided in bed-bound patients and those with swallowing disorders (aspiration lipoid pneumonia risk) 1

Second-Line Therapies (Refractory Cases)

Prucalopride is strongly recommended for patients not responding to over-the-counter agents, though it may cause headache, abdominal pain, nausea, and diarrhea. 2

Linaclotide is FDA-approved for chronic idiopathic constipation (145 mcg daily) and IBS-C (290 mcg daily), taken on empty stomach 30 minutes before meals. 6 Contraindicated in children under 2 years due to fatal dehydration risk. 6

Rectal Therapies

Suppositories and enemas are preferred first-line therapy when DRE identifies full rectum or fecal impaction. 1, 2

Absolute contraindications to enemas: 1, 2

• Neutropenia or thrombocytopenia
• Paralytic ileus or intestinal obstruction
• Recent colorectal or gynecological surgery
• Recent anal/rectal trauma
• Severe colitis, abdominal inflammation, or infection
• Toxic megacolon
• Undiagnosed abdominal pain
• Recent pelvic radiotherapy

Special Populations

Opioid-Induced Constipation

All patients receiving opioid analgesics must be prescribed prophylactic laxatives unless contraindicated by pre-existing diarrhea. 1, 3

• First-line: Osmotic or stimulant laxatives 1, 3
• Avoid bulk laxatives 1, 2
• Combined opioid/naloxone formulations reduce OIC risk 1
• Peripherally acting mu-opioid receptor antagonists (PAMORAs) for unresolved cases 1, 7, 8

Elderly Patients

Particular attention to medication review, comorbidities (cardiac/renal disease), and living situation is essential. 1, 3

• PEG 17g daily offers optimal efficacy and tolerability 1, 2, 3
• Ensure toilet access, especially with mobility limitations 1, 3
• Monitor for dehydration and electrolyte imbalances when using diuretics or cardiac glycosides 1
• Avoid bulk agents in non-ambulatory patients with low fluid intake 1, 3
• Isotonic saline enemas preferred over sodium phosphate enemas 1

Fecal Impaction

Manual disimpaction (digital fragmentation and extraction) is best practice in absence of perforation or bleeding risk, followed by maintenance bowel regimen. 1 Glycerin suppositories may be used for less severe cases. 2

Treatment Algorithm

1. Implement all non-pharmacological measures (hydration ≥1.5L/day, mobility, toileting routine, footstool positioning) 1, 2, 3

2. Add PEG 17g daily OR stimulant laxative (senna/bisacodyl) 1, 2, 3

3. If rectal fullness on DRE: Use suppositories/enemas first 1, 2

4. If inadequate response after 2 weeks: Consider prucalopride or linaclotide 2, 6

5. For persistent symptoms: Perform anorectal testing to evaluate for defecatory disorders 8

Critical Pitfalls to Avoid

• Never increase fiber without ensuring adequate hydration—this worsens constipation 2, 3
• Never use bulk laxatives for opioid-induced constipation 1, 2
• Never delay prophylactic laxatives when initiating opioids 1, 3
• Never use magnesium-containing laxatives in renal insufficiency 1, 2
• Never administer enemas to neutropenic, thrombocytopenic, or post-surgical patients 1, 2
• Never rely on docusate alone—it lacks efficacy 1, 3