What are the treatment options for constipation?

Treatment of Constipation

For general constipation, start with osmotic laxatives (polyethylene glycol or lactulose) or stimulant laxatives (senna or bisacodyl) as first-line pharmacologic therapy, combined with lifestyle modifications including increased fluid intake and physical activity. 1

Initial Assessment

Before initiating treatment, perform a focused evaluation to identify underlying causes and rule out serious pathology:

• Conduct a digital rectal examination to assess for fecal impaction or rectal masses 1, 2
• Check for obstruction through abdominal examination; consider plain abdominal X-ray if symptoms are severe or sudden onset 1, 2
• Review all medications for constipating agents (opioids, anticholinergics, antidepressants, antacids) and discontinue non-essential ones 1, 3, 2
• Evaluate for metabolic causes including hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus if clinically indicated 1, 3, 2

First-Line Treatment: Lifestyle Modifications

Implement these measures for all patients as foundational therapy:

• Increase fluid intake to adequate levels (specific target based on patient tolerance) 1
• Encourage physical activity and mobility within patient's functional limits, even bed-to-chair transfers 1
• Optimize toileting habits: ensure privacy, proper positioning (consider footstool to assist gravity), and scheduled attempts 30 minutes after meals 1
• Increase dietary fiber to 25 g/day for simple constipation, though evidence for pain reduction is mixed 1

First-Line Pharmacologic Treatment

When lifestyle modifications are insufficient, initiate laxative therapy:

Preferred Options (Choose One):

Osmotic Laxatives (generally preferred):

• Polyethylene glycol (PEG): 1 capful (17g) in 8 oz water twice daily 1, 2
• Lactulose: 30-60 mL daily to twice daily (note: 2-3 day latency period, may cause bloating) 1, 2
• Magnesium salts (hydroxide or citrate): 30-60 mL daily to twice daily 1, 2

Stimulant Laxatives:

• Senna: 2-3 tablets twice to three times daily 1, 2
• Bisacodyl: 10-15 mg daily to three times daily 1, 2

Key Considerations:

• PEG offers excellent safety profile, particularly for elderly patients 1
• Avoid magnesium-based laxatives in renal impairment due to hypermagnesemia risk 1
• Do not use bulk laxatives (psyllium) for opioid-induced constipation - they are ineffective and may worsen symptoms 1

Second-Line Treatment: Combination Therapy

If single-agent therapy fails after 4+ weeks:

• Combine osmotic and stimulant laxatives for synergistic effect 2
• Add rectal interventions if oral medications insufficient:
  • Glycerin or bisacodyl suppositories: 1 rectally daily to twice daily 2
  • Phosphate or tap water enemas until clear 2
  • Suppositories and enemas are first-line when digital rectal exam identifies full rectum or fecal impaction 1

Contraindications for enemas: neutropenia, thrombocytopenia, paralytic ileus, recent colorectal/gynecological surgery, recent anal trauma, severe colitis, toxic megacolon, undiagnosed abdominal pain, or recent pelvic radiotherapy 1

Special Situation: Opioid-Induced Constipation

All patients receiving opioid analgesics should be prescribed prophylactic laxatives unless contraindicated by pre-existing diarrhea 1:

• Start prophylactic stimulant laxative (senna preferred) with or without stool softener when opioids initiated 1
• Avoid stool softeners alone - one study showed docusate added to senna was less effective than senna alone 1
• Do not use bulk laxatives for opioid-induced constipation 1

If standard laxatives fail:

• Methylnaltrexone: 0.15 mg/kg subcutaneously every other day (maximum once daily) 1, 2
• Combined opioid/naloxone preparations reduce risk of opioid-induced constipation 1
• Peripherally acting mu-opioid receptor antagonists (PAMORAs) including naloxegol may be valuable 1, 2

Critical Warning: Do NOT use methylnaltrexone in postoperative ileus or mechanical bowel obstruction 3

Third-Line Treatment: Advanced Therapies

For refractory constipation not responding to standard laxatives:

• Secretagogues (linaclotide, plecanatide): FDA-approved for chronic idiopathic constipation and IBS-C in adults, and functional constipation in pediatrics 6-17 years 1, 2, 4
• Prokinetic agents (metoclopramide 10-20 mg PO four times daily, prucalopride): stimulate gastrointestinal motility 1, 3, 2
  • Note: Chronic metoclopramide use carries risk of tardive dyskinesia 1

Management of Fecal Impaction

When digital rectal exam identifies impaction:

• Manual disimpaction (digital fragmentation and extraction) following pre-medication with analgesic and/or anxiolytic 1, 2
• Glycerin suppositories may facilitate removal 1
• Implement maintenance bowel regimen immediately after disimpaction to prevent recurrence 1

Special Considerations for Elderly Patients

Elderly patients require particular attention due to higher risk and unique considerations:

• Ensure toilet access, especially with decreased mobility 1
• Provide dietetic support to manage decreased food intake, anorexia of aging, and chewing difficulties 1
• PEG 17g/day is preferred due to excellent safety profile in elderly 1
• Avoid liquid paraffin in bed-bound patients or those with swallowing disorders due to aspiration pneumonia risk 1
• Monitor closely if on diuretics or cardiac glycosides for dehydration and electrolyte imbalances 1
• Individualize laxative choice based on cardiac and renal comorbidities and drug interactions 1

Adjunctive Therapies

Abdominal massage may provide benefit, particularly in patients with neurogenic problems, though evidence is limited to small studies 1

Monitoring and Reassessment

• Goal: one non-forced bowel movement every 1-2 days 1, 3
• Reassess within 24-48 hours to determine response to therapy 2
• If constipation persists, reassess for cause and severity, rule out obstruction or impaction, and escalate therapy 1, 3
• Consider referral for specialized testing (colonic transit studies, anorectal manometry) for chronic refractory cases 2

Common Pitfalls to Avoid

• Failing to rule out impaction or obstruction before aggressive laxative use 3, 2
• Using sodium-containing laxatives in patients at risk for fluid retention 1
• Inadequate dosing or premature discontinuation of laxatives 2
• Not addressing underlying medication causes of constipation 3, 2
• Using bulk laxatives for opioid-induced constipation - they are ineffective 1