Medications for Gallstone Dissolution
Ursodeoxycholic acid (UDCA) is the most effective medication for dissolving gallstones, typically administered at a dose of 8-10 mg/kg/day for up to 2 years to achieve dissolution of cholesterol gallstones. 1
How UDCA Works to Dissolve Gallstones
UDCA works through several mechanisms to dissolve gallstones:
- Suppresses hepatic synthesis and secretion of cholesterol
- Inhibits intestinal absorption of cholesterol
- Changes bile from cholesterol-precipitating to cholesterol-solubilizing
- Causes dispersion of cholesterol as liquid crystals in aqueous media
- Increases the concentration level at which saturation of cholesterol occurs 1
Effectiveness and Success Factors
The effectiveness of UDCA for gallstone dissolution depends on several factors:
- Stone size: Complete dissolution can be anticipated in about 30% of patients with uncalcified gallstones <20 mm in maximal diameter 1
- Stone composition: Patients with floating stones (high cholesterol content) have up to 50% chance of dissolution 1
- Stone calcification: Calcified gallstones rarely dissolve 1
- Treatment duration: Treatment requires months of therapy, typically up to 2 years 1
- Stone diameter: 81% dissolution rate for stones up to 5 mm in diameter 1
Dosing Guidelines
- Optimal dose: 8-10 mg/kg/day appears to be the most effective dose 1
- Duration: Treatment typically continues for 6 months to 2 years 1
- Monitoring: Serial ultrasonographic examinations should be obtained to monitor stone dissolution 1
Important Considerations and Limitations
- Functioning gallbladder required: A functioning gallbladder is necessary for UDCA to work effectively 2
- Recurrence risk: Stone recurrence after dissolution occurs in up to 50% of patients within 5 years 1
- Not for all stones: UDCA is ineffective for:
- Calcified gallstones
- Stones >20 mm in diameter
- Pigment stones 3
- Partial dissolution: Partial stone dissolution within 6 months indicates >70% chance of eventual complete dissolution 1
Patient Selection
The ideal candidates for UDCA therapy are patients with:
- Small (<20 mm), radiolucent (cholesterol) gallstones
- Functioning gallbladder (visualized on imaging)
- No severe liver disease or biliary obstruction 2
Preventive Use
UDCA is also effective for gallstone prevention in high-risk situations:
- For patients undergoing rapid weight loss (bariatric surgery)
- Recommended dose: 500-600 mg daily for 6 months
- Reduces gallstone formation from 23% (placebo) to 1-9% in patients after gastric bypass surgery 4, 1
Common Pitfalls to Avoid
- Treating calcified stones: UDCA will not dissolve calcified or pigment stones
- Discontinuing too early: Treatment requires months to years for complete dissolution
- Ignoring recurrence risk: Follow-up imaging is essential after successful dissolution
- Treating patients with non-functioning gallbladders: UDCA requires a functioning gallbladder to be effective
- Expecting immediate results: Dissolution is a gradual process, though biliary symptoms often improve within 3 months 5
UDCA is generally well-tolerated with minimal side effects, making it a safe alternative to surgery for selected patients with gallstones 5.