What are the treatment options for constipation?

Treatment of Constipation

Start with osmotic laxatives (polyethylene glycol, lactulose, or magnesium salts) or stimulant laxatives (senna, bisacodyl, sodium picosulfate) as first-line pharmacological therapy, combined with non-pharmacological measures including increased fluid intake and physical activity. 1, 2

Initial Assessment

Before initiating treatment, perform a focused evaluation:

• Conduct abdominal examination, perineal inspection, and digital rectal examination to identify fecal impaction or rectal masses 1, 2
• Check corrected calcium and thyroid function if metabolically-driven constipation is suspected (hypercalcemia, hypothyroidism) 1, 2
• Consider plain abdominal X-ray to assess fecal loading extent and exclude bowel obstruction 1, 2
• Identify and discontinue non-essential constipating medications 2

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

Implement these measures before or alongside pharmacological therapy:

• Ensure privacy and comfortable positioning during defecation; a small footstool helps facilitate proper straining mechanics 1, 2
• Increase fluid intake to adequate levels 1, 2
• Increase physical activity and mobility within patient limitations, even bed-to-chair transfers 1, 2
• Add dietary fiber (9-12 g for children under 6 years; 12-18 g for older children and adults) only if fluid intake is adequate 1, 2, 3
  • Psyllium is most effective among fiber types, requiring doses >10 g/day for at least 4 weeks 3
  • Avoid bulk laxatives like psyllium in opioid-induced constipation as they are ineffective 1
• Consider abdominal massage, particularly for patients with neurogenic bowel dysfunction 1, 2

Pharmacological Treatment Algorithm

Standard Constipation (Non-Opioid-Induced)

First-line laxatives:

• Osmotic laxatives: Polyethylene glycol (PEG 17 g/day), lactulose, or magnesium salts 1, 2

  • PEG is particularly safe and effective in elderly patients 1, 2
  • Use magnesium salts cautiously in renal impairment due to hypermagnesemia risk 1, 2

• Stimulant laxatives: Senna, bisacodyl (10-15 mg, 2-3 times daily), cascara, or sodium picosulfate 1, 2

  • Goal: 1 non-forced bowel movement every 1-2 days 1

Second-line options if first-line fails:

• Rectal bisacodyl once daily 1
• Secretagogues (linaclotide, lubiprostone, plecanatide) for refractory cases 1
• Prokinetic agents (metoclopramide) if gastroparesis is suspected 1

Opioid-Induced Constipation (OIC)

Prophylaxis is mandatory:

• Prescribe a concomitant laxative with all opioid therapy unless pre-existing diarrhea is present 1, 2
• Use osmotic or stimulant laxatives as first-line 1, 2

For refractory OIC:

• Methylnaltrexone 0.15 mg/kg subcutaneously every other day (maximum once daily) for constipation unresponsive to standard laxatives 1, 2
  • Contraindicated in postoperative ileus or mechanical bowel obstruction 1
• Naloxegol (peripherally-acting μ-opioid receptor antagonist) as alternative 1
• Combined opioid/naloxone preparations reduce OIC risk 1
• Lubiprostone (prostaglandin analog) can be combined with methylnaltrexone 1

Fecal Impaction

When digital rectal examination identifies impaction:

• Perform digital fragmentation and manual extraction of stool 1, 2
• Administer glycerin suppositories for less severe impaction 1
• Use suppositories and enemas as first-line therapy when rectum is full on examination 1, 2
• Follow with maintenance bowel regimen to prevent recurrence 1, 2

Enema contraindications: neutropenia, thrombocytopenia, paralytic ileus, intestinal obstruction, recent colorectal/gynecological surgery, recent anal/rectal trauma, severe colitis, toxic megacolon, undiagnosed abdominal pain, or recent pelvic radiotherapy 1

Special Populations

Elderly Patients

• Use PEG 17 g/day as preferred agent due to excellent safety profile 1, 2
• Ensure toilet access, especially with decreased mobility 1, 2
• Educate on optimal toileting: attempt defecation twice daily, 30 minutes after meals, strain no more than 5 minutes 1
• Avoid liquid paraffin in bedridden patients or those with swallowing disorders due to aspiration lipoid pneumonia risk 1, 2
• Use saline laxatives (magnesium hydroxide) cautiously due to hypermagnesemia risk 1
• Monitor closely if on diuretics or cardiac glycosides for dehydration and electrolyte imbalances 1, 2
• Prefer isotonic saline enemas over sodium phosphate enemas to minimize adverse effects 1

Common Pitfalls

• Do not add fiber without adequate fluid intake as this worsens constipation 1, 2
• Avoid bulk agents in non-ambulatory patients with low fluid intake due to mechanical obstruction risk 1
• Do not use psyllium for opioid-induced constipation as it is ineffective 1
• Remember that complete symptom resolution is often unachievable; manage patient expectations accordingly 1