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, perform a focused evaluation to identify reversible causes and complications:

• Check for fecal impaction through digital rectal examination (DRE), as this requires immediate disimpaction rather than oral laxatives 2
• Rule out bowel obstruction using plain abdominal X-ray if clinically suspected 2
• Screen for metabolic causes: hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 2, 1
• Review all medications for constipating agents (opioids, anticholinergics, antacids) 2
• Assess mobility and toileting access, particularly in elderly patients 2

Stepwise Treatment Algorithm

First-Line: Stimulant Laxatives

• Senna or bisacodyl 10-15 mg, 2-3 times daily 2, 1
• Do NOT add docusate (stool softeners) to senna—evidence shows no additional benefit 1, 3
• Combine with non-pharmacologic measures: increased fluid intake, physical activity within patient limits, privacy for defecation, and proper positioning (footstool to assist gravity) 2

Second-Line: Add Osmotic Laxatives

If constipation persists after 1-2 weeks of stimulant therapy, add one of the following 2, 1:

• Polyethylene glycol (PEG) 17g mixed with 8 oz water twice daily 1, 3
• Lactulose 2
• Magnesium hydroxide or magnesium citrate (use cautiously in renal impairment due to hypermagnesemia risk) 2
• Rectal bisacodyl 2, 1

Third-Line: Prokinetic Agents

If gastroparesis is suspected (bloating, early satiety, nausea), add 1:

• Metoclopramide 10-20 mg, 2-3 times daily 2, 1

Fourth-Line: Intestinal Secretagogues

For persistent constipation unresponsive to standard laxatives 1, 4:

• Linaclotide, lubiprostone, or plecanatide 1, 5

Special Situations

Opioid-Induced Constipation

• Prescribe prophylactic laxatives (osmotic or stimulant) to all patients starting opioids unless they have pre-existing diarrhea 2
• Avoid bulk laxatives (psyllium) as they are ineffective for opioid-induced constipation 2
• For refractory cases, consider peripherally acting μ-opioid receptor antagonists (PAMORAs) such as methylnaltrexone 0.15 mg/kg every other day 2, 4
• Combined opioid/naloxone formulations reduce constipation risk 2

Fecal Impaction

• Perform digital disimpaction (manual fragmentation and extraction) when DRE identifies a full rectum 2
• Use glycerin suppositories or enemas as rescue therapy 2, 3
• Contraindications to enemas: neutropenia, thrombocytopenia, paralytic ileus, recent colorectal/gynecological surgery, recent pelvic radiation, severe colitis, or undiagnosed abdominal pain 2
• Follow disimpaction with maintenance laxative regimen to prevent recurrence 2

Elderly Patients

• Ensure toilet access for patients with decreased mobility 2
• Provide dietetic support and manage decreased food intake (anorexia of aging, chewing difficulties) 2
• Educate patients to attempt defecation twice daily, 30 minutes after meals, straining no more than 5 minutes 2

Critical Pitfalls to Avoid

• Do not rely on fiber supplements alone—they are ineffective for medication-induced constipation and require adequate hydration (at least 2 liters daily) to work 1, 6, 7
• Psyllium is contraindicated for opioid-induced constipation and may worsen symptoms 2, 1
• Stool softeners provide no benefit when added to stimulant laxatives 1, 3
• Reassess for impaction or obstruction if constipation persists despite escalating therapy 1
• Abdominal massage may help patients with neurogenic bowel dysfunction 2

Treatment Goals

• Aim for one non-forced bowel movement every 1-2 days, not necessarily daily 2, 1
• Most patients respond within 12-72 hours to appropriate laxative therapy 8
• If constipation persists beyond 7 days or rectal bleeding occurs, stop treatment and investigate for serious underlying conditions 9, 8