What is the treatment algorithm for constipation?

Treatment Algorithm for Constipation

Begin with discontinuing constipating medications and initiating a therapeutic trial of fiber supplementation and/or osmotic or stimulant laxatives before pursuing any diagnostic testing. 1

Initial Management (First-Line Therapy)

Step 1: Medication Review and Lifestyle Modifications

• Discontinue all medications that can cause constipation when feasible before further evaluation 1
• Ensure privacy and comfort for normal defecation, use positioning aids like footstools to assist gravity, and increase fluid intake and physical activity within patient limits 1
• Educate patients to attempt defecation at least twice daily, preferably 30 minutes after meals, straining no more than 5 minutes 1

Step 2: First-Line Pharmacologic Therapy

Start with osmotic laxatives (polyethylene glycol 17g daily, lactulose, or magnesium salts) OR stimulant laxatives (senna, bisacodyl, glycerol suppositories) 1

• Polyethylene glycol offers efficacy with good tolerability, especially in elderly patients 1
• Magnesium and sulfate salts should be used cautiously in renal impairment due to hypermagnesemia risk 1
• Stimulant laxatives can be administered 30 minutes after meals to synergize with the gastrocolonic response 1
• Bulk laxatives like psyllium are NOT recommended for opioid-induced constipation 1
• Daily cost for these agents is approximately $1 or less 1

Step 3: Rectal Interventions for Fecal Loading

• Suppositories and enemas are first-line therapy when digital rectal examination identifies a full rectum or fecal impaction 1
• Enemas are contraindicated in neutropenia, thrombocytopenia, paralytic ileus, recent colorectal/gynecologic surgery, recent anal trauma, severe colitis, toxic megacolon, undiagnosed abdominal pain, or recent pelvic radiotherapy 1

Diagnostic Testing (For Non-Responders)

Step 4: When to Pursue Testing

Perform anorectal testing only in patients who do not respond to the initial therapeutic trial 1

• Conduct a careful digital rectal examination including assessment of pelvic floor motion during simulated evacuation before referral for anorectal manometry 1
• A normal digital rectal examination does NOT exclude defecatory disorders 1
• In the absence of alarm features (blood in stool, anemia, weight loss), only a complete blood count is necessary 1
• Do NOT perform metabolic tests (glucose, calcium, TSH) unless other clinical features warrant it 1
• Do NOT perform colonoscopy without alarm features unless age-appropriate colon cancer screening has not been done 1
• Evaluate colonic transit if anorectal test results do not show a defecatory disorder or if symptoms persist despite treatment of a defecatory disorder 1

Second-Line Therapy (For Refractory Cases)

Step 5: Advanced Pharmacologic Agents

When symptoms do not respond to simple laxatives, consider newer agents like linaclotide or lubiprostone 1

• Linaclotide 145 mcg once daily for chronic idiopathic constipation or 290 mcg once daily for IBS-C 2
• Linaclotide increases complete spontaneous bowel movements by approximately 1.5 per week compared to placebo 2
• Daily cost for these newer agents is $7-9 1
• Secretagogues like linaclotide soften stools and accelerate gut transit by activating ion channels on enterocytes 1

Step 6: Opioid-Induced Constipation Specific Management

• All patients receiving opioid analgesics should be prescribed a concomitant laxative unless contraindicated by pre-existing diarrhea 1
• Combined opioid/naloxone medications reduce the risk of opioid-induced constipation 1
• For unresolved opioid-induced constipation, peripherally acting mu-opioid receptor antagonists (PAMORAs) may be valuable 1

Treatment Based on Constipation Subtype

Step 7: Defecatory Disorders

Pelvic floor retraining by biofeedback therapy rather than laxatives is the treatment of choice for defecatory disorders 1

• Biofeedback therapy improves symptoms in more than 70% of patients with defecatory disorders 1, 3
• Biofeedback trains patients to relax pelvic floor muscles during straining and correlate relaxation with pushing to achieve defecation 1
• The motivation of patient and therapist, frequency and intensity of retraining, and involvement of behavioral psychologists and dietitians contribute to success 1, 3
• Initial treatment should continue for 6-8 weeks with regular follow-up 3

Step 8: Normal Transit and Slow Transit Constipation

Normal transit constipation (NTC) and slow transit constipation (STC) can be safely managed with long-term use of laxatives 1

• Continue osmotic and/or stimulant laxatives as needed 1
• Consider newer agents (linaclotide, lubiprostone) for refractory cases 1

Surgical Options (Last Resort)

Step 9: Surgical Intervention for Severe Slow Transit Constipation

Surgery is indicated only after failure of an aggressive, prolonged trial of laxatives, fiber, and prokinetic agents, and only in well-documented slow transit constipation 1

• Total colectomy with ileorectal anastomosis is the procedure of choice 1
• Must exclude coexistent upper gastrointestinal motility disorders and defecatory disorders before surgery 1
• Even in tertiary centers, only 5% of highly selected cases justify surgical treatment 1
• In patients with severe bloating and abdominal pain, a venting ileostomy may help determine if symptoms are attributable to small intestine or colon 1
• Patients must understand that surgery treats constipation but may not relieve other symptoms like abdominal pain 1

Step 10: Refractory Defecatory Disorders After Biofeedback Failure

• Options are limited for patients with refractory defecatory disorders after adequate biofeedback trial 1
• Venting ileostomy or colostomy (if colonic transit is normal) are viable fallback options 1
• Botulinum toxin injection or stapled transanal resection cannot be recommended outside of clinical trials 1

Critical Pitfalls to Avoid

• Do not perform extensive metabolic testing or colonoscopy without alarm features or appropriate screening indications 1
• Do not use bulk laxatives in opioid-induced constipation or in non-ambulatory patients with low fluid intake 1
• Do not proceed to surgery without excluding defecatory disorders and upper GI motility disorders 1
• Do not skip biofeedback therapy in patients with defecatory disorders—it is more effective than laxatives 1
• Avoid liquid paraffin in bed-bound patients and those with swallowing disorders due to aspiration pneumonia risk 1
• Monitor for dehydration and electrolyte imbalances in elderly patients on diuretics or cardiac glycosides when using laxatives 1