What is the fastest method to treat constipation?

Fastest Methods to Treat Constipation

Polyethylene glycol (PEG) is the fastest and most effective method to treat constipation, with significant improvement in bowel movements typically occurring within 24-48 hours. 1

First-Line Rapid Interventions

Immediate Relief Options

• Osmotic Laxatives:

  • PEG 3350 (17g mixed in 8 ounces of water once daily) - provides fastest relief with increased bowel movements 1
  • Magnesium citrate (8 oz) or magnesium hydroxide (30-60 mL) - works within hours 1

• Stimulant Laxatives (if immediate relief needed):

  • Bisacodyl 10-15 mg orally or as suppository (works within 6-12 hours) 1
  • Senna (2-3 tablets) - effective within 6-12 hours 1

• Rectal Options (for fastest relief):

  • Glycerin suppository - works within 15-30 minutes 1
  • Tap water or saline enema - provides relief within minutes to an hour 1

Algorithm for Treatment Based on Severity

For Mild Constipation

1. Increase fluid intake (8-10 glasses daily) 1, 2
2. Add fiber supplement (psyllium 15g daily) - Note: This works more slowly (24-72 hours) 1
3. If no response within 24 hours, add PEG 3350 1

For Moderate to Severe Constipation

1. Start with PEG 3350 (17g daily) 1
2. If no response within 24 hours, add stimulant laxative (bisacodyl 10-15mg) 1
3. For severe cases, consider glycerin suppository or enema for immediate relief 1

For Opioid-Induced Constipation

1. Stimulant laxative + stool softener prophylactically 1
2. If persistent, consider methylnaltrexone 0.15 mg/kg subcutaneously 1

Important Considerations

• Rule out impaction: If severe constipation with overflow diarrhea, check for impaction before administering oral laxatives 1
• Check for obstruction: Physical exam and possibly abdominal X-ray if severe symptoms 1
• Discontinue constipating medications if possible 1

Common Pitfalls to Avoid

• Relying solely on fiber for acute constipation - fiber works slowly and can worsen symptoms initially 1, 3
• Insufficient fluid intake with fiber supplements - can worsen constipation 1, 2
• Overuse of stimulant laxatives - can lead to dependence; use PEG as first-line 1
• Ignoring underlying causes - check for metabolic issues (hypercalcemia, hypothyroidism) 1

PEG has demonstrated superior efficacy compared to other treatments with an increase in complete spontaneous bowel movements of 2.90 per week over placebo, making it the most reliable option for rapid relief 1. While fiber is often recommended, it typically takes several days to work and should be combined with adequate fluid intake to be effective 1, 2.