What are the treatment options for chronic constipation?

Treatment of Chronic Constipation

For chronic constipation in adults, start with polyethylene glycol (PEG) 17g once daily, which has strong evidence for efficacy and is the most effective first-line pharmacological treatment. 1

Stepwise Treatment Algorithm

Step 1: Initial Pharmacological Therapy

• Polyethylene glycol (PEG) is the recommended first-line treatment with moderate certainty evidence showing it increases complete spontaneous bowel movements by approximately 2.9 per week and improves global symptom relief in 45% of patients. 1
• PEG 17g mixed in 8 ounces of liquid once daily is the standard dose, with durable response demonstrated over 6 months. 1
• Side effects include abdominal distension, loose stools, flatulence, and nausea, but serious adverse events are rare. 1

Step 2: Adjunctive or Alternative First-Line Options

For mild constipation or patients preferring non-prescription options, consider fiber supplementation (conditional recommendation):

• Psyllium is the only fiber supplement with demonstrated efficacy among evaluated fiber types; bran and inulin have very limited data. 1
• Recommend at least 20-25g total daily fiber intake, taken with 8-10 ounces of fluid per dose. 1, 2
• Fiber should be increased gradually over several days to minimize flatulence and bloating. 2
• Fiber can be used alone for mild symptoms or combined with PEG for moderate-to-severe constipation. 1

Step 3: Second-Line Pharmacological Options

If PEG fails or is not tolerated, escalate to prescription medications with strong evidence:

• Sodium picosulfate (stimulant laxative) - strong recommendation 1
• Linaclotide 145 mcg once daily (secretagogue) - strong recommendation, increases CSBMs by ~1.5 per week and improves stool consistency 1, 3
• Plecanatide (secretagogue) - strong recommendation 1
• Prucalopride (serotonin-4 agonist) - strong recommendation 1

Step 4: Additional Prescription Options

For patients not responding to above agents, consider:

• Lubiprostone 24 mcg twice daily with food (conditional recommendation) - activates chloride channels to enhance intestinal fluid secretion. 4, 5
• Nausea occurs in up to 31% of patients but is reduced when taken with food and water. 4
• Monthly cost approximately $374, requiring consideration of insurance coverage and prior authorization. 4

Step 5: Other Conditional Recommendations

• Lactulose - conditional recommendation 1
• Senna - conditional recommendation 1
• Magnesium oxide - conditional recommendation 1

Critical Implementation Considerations

Fluid Intake

• Increase fluid intake only in patients consuming less than 500 mL/day or in the lowest quartile of daily fluid intake, as chronically constipated patients generally drink similar amounts as non-constipated individuals. 1
• Standard fiber supplement doses require 8-10 ounces of fluid per dose. 1

Lifestyle Modifications

• Evidence for increased physical activity is weak except in specific populations (elderly, hospitalized, institutionalized, or dehydrated patients). 2
• Dietary fiber from food sources should be assessed before supplementation. 1

Common Pitfalls to Avoid

• Do not use finely ground wheat bran, as it can decrease stool water content and worsen constipation. 1
• Avoid recommending generic "increase fluids and exercise" to all patients—target those with documented low intake. 1, 2
• Do not delay PEG therapy in patients with moderate-to-severe symptoms, as it has the strongest evidence base. 1

Cost and Access Considerations

• PEG, fiber, and most osmotic/stimulant laxatives are available over-the-counter at low cost. 1
• Prescription secretagogues and prokinetics may require prior authorization and have higher out-of-pocket costs. 1, 4
• Generic formulations are not available for all prescription agents, increasing patient expense. 1

Evidence Quality Notes

The 2023 AGA-ACG guideline represents the highest quality evidence available, with strong recommendations (based on moderate certainty evidence) for PEG, sodium picosulfate, linaclotide, plecanatide, and prucalopride. 1 Conditional recommendations for fiber, lactulose, senna, magnesium oxide, and lubiprostone reflect lower certainty evidence but remain reasonable options in appropriate clinical contexts. 1

Linaclotide demonstrates consistent efficacy with CSBM responder rates of 15-20% (versus 3-6% for placebo) and maximum effect by week 1 that is maintained throughout treatment. 3