What is the approach to managing constipation?

Approach to Managing Constipation

The recommended first-line approach for constipation management is polyethylene glycol (PEG), with the addition of stimulant laxatives such as senna or bisacodyl if needed, as this combination has demonstrated strong evidence for effectiveness in improving bowel movements and quality of life. 1, 2

Initial Assessment and Classification

Key Diagnostic Elements

• Evaluate stool frequency, consistency, straining, sensation of incomplete evacuation, and need for manual maneuvers
• Perform abdominal examination for masses, tenderness, or distension
• Conduct digital rectal examination to assess anal tone, masses, impaction, and evacuation ability
• Complete blood count for all patients; metabolic tests only if clinically indicated

Red Flag Symptoms Requiring Further Investigation

• Rectal bleeding
• Unintentional weight loss
• Change in stool caliber
• Progressive abdominal pain
• Age >50 without appropriate colorectal cancer screening

Treatment Algorithm

Step 1: Lifestyle Modifications

• Increase fluid intake to at least 8 glasses of water daily
• Gradually increase dietary fiber to 20-25g per day
• Increase physical activity within patient limits
• Optimize toileting habits: regular schedule, privacy, and using footstool to elevate knees above hips

Step 2: First-Line Pharmacological Therapy

• Polyethylene glycol (PEG) 3350 - strongly recommended based on high-quality evidence 1
• PEG works by increasing water in the colon and has demonstrated superior efficacy compared to placebo with minimal side effects

Step 3: Add Stimulant Laxatives if Needed

• Add senna or bisacodyl if PEG alone is insufficient 1, 2
• Stimulant laxatives increase intestinal motility and are particularly effective when combined with osmotic agents

Step 4: Consider Alternative or Additional Agents

For refractory cases, consider:

• Secretagogues (linaclotide, plecanatide) - strongly recommended for chronic idiopathic constipation 1, 3
• Prucalopride (serotonin type 4 agonist) - strongly recommended for chronic idiopathic constipation 1
• Lubiprostone - conditionally recommended for chronic idiopathic constipation 1

Step 5: Special Considerations for Opioid-Induced Constipation

• Start prophylactic bowel regimen when initiating opioid therapy
• Consider peripherally acting mu-opioid receptor antagonists (PAMORAs) like methylnaltrexone for refractory cases
• PAMORAs are contraindicated in patients with gastrointestinal perforation risk or mechanical bowel obstruction 2

Specific Treatment Recommendations by Constipation Type

Chronic Idiopathic Constipation

• First-line: PEG 3350 with adequate hydration
• Second-line: Add stimulant laxatives (senna, bisacodyl)
• Third-line: Consider secretagogues like linaclotide (145 mcg daily) 1, 3

Opioid-Induced Constipation

• Prophylactic stimulant laxatives with stool softeners when initiating opioid therapy
• Avoid bulk-forming laxatives which may worsen obstruction
• For refractory cases: Consider methylnaltrexone 0.15mg/kg subcutaneously every other day 2

Dyssynergic Defecation

• Biofeedback therapy and pelvic muscle re-education are most effective 4, 5
• Continue osmotic and stimulant laxatives as needed during retraining

Monitoring and Reassessment

• Reassess treatment efficacy within 2-4 weeks of initiating therapy
• Goal: One non-forced bowel movement every 1-2 days
• Use Bowel Function Index to assess severity and monitor response (score ≥30 indicates clinically significant constipation requiring escalation)

Important Cautions and Contraindications

• Avoid bulk-forming laxatives in patients with severe constipation or suspected obstruction
• Docusate has not shown benefit and is not recommended based on available literature
• Do not continue ineffective treatments without reassessment
• PAMORAs should not be used as first-line treatment or in patients with bowel obstruction risk

Fiber supplementation alone, while often recommended, has shown inconsistent results and should be considered as part of a comprehensive approach rather than sole therapy for constipation 6. The most effective management combines appropriate pharmacological therapy with lifestyle modifications tailored to the specific constipation subtype.