What is the recommended treatment for constipation using a stool softener, such as Colace (docusate sodium)?

Stool Softeners for Constipation Management

Stool softeners like docusate sodium (Colace) are not recommended as first-line agents for constipation management due to lack of efficacy evidence. 1

Efficacy of Docusate Sodium

• Docusate sodium works as a surfactant agent that theoretically allows water and lipids to penetrate stool to hydrate and soften fecal material 2, 1
• Despite widespread use, docusate has shown inadequate experimental evidence supporting its efficacy in constipation management 1, 3
• Clinical studies have demonstrated that docusate does not increase stool water content or frequency compared to placebo 3
• A randomized controlled trial found that docusate plus sennosides was actually less effective than sennosides alone in producing bowel movements in hospitalized cancer patients 4
• Another study showed that psyllium was superior to docusate for softening stools by increasing stool water content and had greater overall laxative efficacy 5
• In hospice patients, a randomized trial found no significant benefit of docusate plus sennosides compared to placebo plus sennosides 6

Recommended First-Line Treatments for Constipation

Preventive Measures

• Maintain adequate fluid intake 2
• Increase physical activity when appropriate 2
• Increase dietary fiber if adequate fluid intake and physical activity are possible 2
• Discontinue any non-essential constipating medications 2

First-Line Pharmacologic Therapy

• Stimulant laxatives are recommended as first-line agents 2, 1:
  • Senna: 2 tablets every morning; maximum 8-12 tablets per day 2
  • Bisacodyl: 10-15 mg daily to three times daily 2
• Osmotic laxatives are also effective first-line options 2, 1:
  • Polyethylene glycol (PEG): 1 capful in 8 oz water twice daily 2
  • Lactulose: 30-60 mL daily to four times daily 2
  • Magnesium citrate or magnesium hydroxide: 30-60 mL daily to twice daily 2

Management Algorithm for Constipation

1. Initial Assessment:

   • Rule out bowel obstruction 2
   • Check for impaction 2
   • Identify and treat other causes (e.g., hypercalcemia, hypokalemia, hypothyroidism, diabetes mellitus) 2

2. First-Line Treatment:

   • Start with a stimulant laxative (senna or bisacodyl) 2
   • Titrate stimulant laxative as needed with goal of one non-forced bowel movement every 1-2 days 2

3. If Constipation Persists:

   • Add an osmotic laxative (PEG, lactulose, or magnesium salts) 2
   • Consider glycerin suppository or bisacodyl suppository for acute relief 2
   • For severe cases, consider tap water enema until clear 2

4. For Opioid-Induced Constipation:

   • Increase dose of laxative when increasing dose of opioids 2
   • If laxative therapy is insufficient, consider peripherally acting μ-opioid receptor antagonists:
     • Methylnaltrexone: 0.15 mg/kg subcutaneously every other day (no more than once daily) 2
     • Naldemedine or naloxegol for laxative-refractory opioid-induced constipation 2

Special Considerations

• For cancer patients, prophylactic laxative regimens should focus on stimulant laxatives rather than docusate 2, 1
• Opioid-induced constipation does not improve over time with tolerance, unlike other opioid side effects 2
• Fiber supplements like Metamucil are unlikely to control opioid-induced constipation and are not recommended 2
• Consider use of a prokinetic agent (e.g., metoclopramide) for persistent constipation 2

Common Pitfalls to Avoid

• Relying solely on stool softeners like docusate sodium, which have limited evidence of efficacy 1, 4, 6
• Failing to increase laxative doses when opioid doses are increased 2
• Using fiber supplements as the primary treatment for opioid-induced constipation 2
• Not addressing constipation prophylactically in patients starting opioid therapy 2
• Overlooking potential causes of constipation beyond medication effects 2