What are the treatment options for constipation?

Treatment of Constipation

Start with a stimulant laxative (senna or bisacodyl 10-15 mg, 2-3 times daily) as first-line therapy, aiming for one non-forced bowel movement every 1-2 days. 1

Initial Assessment

Before initiating treatment, rule out serious underlying conditions:

• Perform digital rectal examination to assess for fecal impaction or rectal masses 2
• Check for bowel obstruction using plain abdominal X-ray if clinically indicated 2
• Evaluate metabolic causes: hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 1, 3
• Review medication list and withdraw inappropriate or unnecessary constipating medications 2
• Abdominal examination and perineal inspection should be performed 2

Stepwise Treatment Algorithm

First-Line: Stimulant Laxatives

Begin with senna or bisacodyl 10-15 mg, 2-3 times daily as the primary treatment 1. This approach is supported by the National Comprehensive Cancer Network guidelines and prioritizes efficacy over traditional fiber-first approaches 1.

Critical pitfall to avoid: Do NOT add stool softeners like docusate to stimulant laxatives—evidence shows no additional benefit 1.

Second-Line: Add Osmotic or Additional Stimulant Laxatives

If constipation persists after first-line therapy, add one of the following 1:

• Polyethylene glycol (PEG/Macrogol) - preferred osmotic agent 2, 3
• Lactulose 2
• Magnesium hydroxide or magnesium citrate (use cautiously in renal impairment due to hypermagnesemia risk) 2
• Rectal bisacodyl 1

Third-Line: Prokinetic Agents

If gastroparesis is suspected, add metoclopramide 10-20 mg, 2-3 times daily 1. This is particularly relevant for patients on medications that slow gastric emptying (such as GLP-1 agonists) 1.

Fourth-Line: Secretagogues

For persistent constipation unresponsive to standard laxatives, consider newer agents 1, 4:

• Linaclotide
• Lubiprostone
• Plecanatide

These intestinal secretagogues have strong evidence for efficacy and safety in refractory cases 4.

Special Situations

Opioid-Induced Constipation

All patients receiving opioid analgesics should be prescribed a concomitant laxative prophylactically unless contraindicated by pre-existing diarrhea 2, 3.

• Osmotic or stimulant laxatives are preferred 2
• Bulk laxatives such as psyllium are NOT recommended for opioid-induced constipation 2, 3
• Combined opioid/naloxone medications can reduce constipation risk 2
• Peripherally acting μ-opiate antagonists (PAMORAs) are effective for unresolved opioid-induced constipation 2, 4, 5

Fecal Impaction

When digital rectal examination identifies a full rectum or fecal impaction 2:

• Suppositories and enemas are preferred first-line therapy 2, 3
• Perform manual disimpaction (digital fragmentation and extraction) if needed 2, 3
• Follow with maintenance bowel regimen to prevent recurrence 2, 3

Contraindications for enemas: 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 2, 3.

Supportive Measures

While pharmacologic therapy is primary, incorporate these measures 2, 3:

• Ensure privacy and comfort for defecation 2, 3
• Use proper positioning with a small footstool to assist gravity 2, 3
• Increase fluid intake (at least 2 liters daily if using fiber) 2, 1, 3
• Increase physical activity within patient limits 2, 3
• Abdominal massage may help, particularly in patients with neurogenic problems 2, 3

Role of Fiber

Fiber supplementation is NOT first-line therapy and has significant limitations 1:

• Dietary fiber should only be considered if the patient has adequate fluid intake (at least 2 liters daily) 1
• Supplemental medicinal fiber (like psyllium) is unlikely to control medication-induced constipation 1
• If used, psyllium and pectin at doses >10 g/day for at least 4 weeks may improve stool frequency and consistency 6
• Water-insoluble fibers (cellulose, hemicellulose) are more effective for laxation than water-soluble fibers 7
• Fiber can cause increased flatulence 6

Elderly Patients

Pay particular attention to elderly patients with constipation 2, 3:

• Ensure access to toilets, especially with decreased mobility 2, 3
• Provide dietetic support and manage decreased food intake 2, 3
• Educate patients to attempt defecation at least twice daily, usually 30 minutes after meals, straining no more than 5 minutes 2

Treatment Goals

Aim for one non-forced bowel movement every 1-2 days, not necessarily daily bowel movements 1. This realistic goal prevents overtreatment and focuses on quality of life rather than arbitrary frequency targets.

When to Reassess

Reassess for impaction or obstruction if constipation persists despite treatment 1. Consider anorectal function testing and colonic transit studies for patients who do not respond to over-the-counter agents 4, 5. Defecatory disorders may respond to biofeedback therapy, while slow-transit constipation may require surgical intervention in selected patients 4, 5.