What are the treatment options for postoperative constipation?

Treatment Options for Postoperative Constipation

For postoperative constipation, a stepwise approach starting with increased fluid intake, dietary fiber, and physical activity, followed by osmotic laxatives like polyethylene glycol and stimulant laxatives like bisacodyl is recommended. 1

First-Line Interventions

• Increase fluid intake to at least 1.5 L/day, varying beverage temperatures and flavors while avoiding carbonated and sugar-sweetened drinks 1
• Increase dietary fiber consumption through fruits, vegetables, and whole grains, but only if adequate fluid intake and physical activity are possible 1
• Encourage physical activity and exercise as appropriate to the patient's postoperative condition 1, 2
• Discontinue any non-essential constipating medications that may be contributing to the problem 1

Pharmacological Management

For Mild Constipation

• Osmotic laxatives are first-line pharmacological options:

  • Polyethylene glycol (PEG) 3350: 1 capful in 8 oz water BID; should be used for 2 weeks or less unless directed by physician 3
  • Lactulose: 30-60 mL BID-QID 1
  • Sorbitol: 30 mL every 2 hours × 3, then as needed 1

• Stimulant laxatives are also effective first-line options:

  • Bisacodyl: 10-15 mg daily to TID with a goal of one non-forced bowel movement every 1-2 days 1
  • Senna (with or without docusate): 2-3 tablets BID-TID 1

For Persistent Constipation

• Rectal interventions if oral medications are ineffective:

  • Glycerin suppositories 1
  • Bisacodyl suppositories: one rectally daily to BID 1
  • Mineral oil retention enema 1

• Additional oral options:

  • Magnesium hydroxide: 30-60 mL daily to BID 1
  • Magnesium citrate: 8 oz daily 1

For Opioid-Induced Postoperative Constipation

• Prophylactic laxative therapy should be initiated when opioids are prescribed 1
• Avoid bulk-forming laxatives such as psyllium for opioid-induced constipation 1
• Consider methylnaltrexone for opioid-induced constipation that doesn't respond to standard laxatives: 0.15 mg/kg subcutaneously every other day (not more than once daily), except in cases of post-operative ileus or mechanical bowel obstruction 1

Special Considerations

• Rule out impaction if diarrhea accompanies constipation (could be overflow around impaction) 1
• Assess for obstruction using physical exam and abdominal x-ray if indicated 1
• Evaluate for other causes of constipation such as hypercalcemia, hypokalemia, hypothyroidism, or diabetes mellitus 1
• Consider prokinetic agents such as metoclopramide (10-20 mg PO QID) if gastroparesis is suspected 1

Risk Factors for Postoperative Constipation

• Female gender, advanced age (>65 years), unemployment status 4
• Lower extremity surgery, opioid analgesic use 4
• Pre-hospital constipation history, chronic disease, regular medication use 4
• Inadequate fluid intake, prolonged hospital stay 4

Monitoring and Follow-up

• Goal of therapy: One non-forced bowel movement every 1-2 days 1
• Reassess regularly for treatment effectiveness and potential complications 1
• If constipation persists despite multiple interventions, consider referral to gastroenterology for further evaluation 5

Pitfalls to Avoid

• Don't delay treatment - postoperative constipation affects up to 39% of orthopedic patients and should be addressed proactively 4
• Don't use bulk-forming laxatives alone without ensuring adequate fluid intake 1, 5
• Avoid prolonged use of stimulant laxatives which can lead to dependence 3
• Don't overlook the importance of non-pharmacological interventions - dietary and lifestyle modifications alone resolved constipation in more than half of patients in one study 6