Ursodeoxycholic Acid Dosing for Gallstone Dissolution
The recommended dose of ursodeoxycholic acid (UDCA) for gallstone dissolution is 8-10 mg/kg/day given in 2 or 3 divided doses. 1
Dosing Considerations
- The FDA-approved dosage for radiolucent gallbladder stone treatment is 8-10 mg/kg/day divided into 2-3 doses 1
- Bedtime administration appears to be more effective than mealtime dosing, potentially allowing for lower effective doses 2
- A "best-buy" regimen of 8.4 mg/kg/day UDCA given at bedtime has been shown to effectively reduce cholesterol saturation index in gallbladder bile 2
- Complete stone dissolution can be anticipated in approximately 30% of unselected patients with uncalcified gallstones <20 mm in maximal diameter treated for up to 2 years 1
Monitoring Treatment Response
- Ultrasound images of the gallbladder should be obtained at 6-month intervals for the first year of therapy to monitor gallstone response 1
- If partial stone dissolution is not observed by 12 months of therapy, the likelihood of success is greatly reduced 1
- If gallstones appear to have dissolved, therapy should be continued and dissolution confirmed on a repeat ultrasound examination within 1-3 months 1
- Partial stone dissolution occurring within 6 months of beginning therapy appears to be associated with a >70% chance of eventual complete stone dissolution with further treatment 1
Factors Affecting Treatment Success
- The chance of gallstone dissolution is increased up to 50% in patients with floating or floatable stones (high cholesterol content) 1
- Success rates are inversely related to stone size for stones <20 mm in maximal diameter, with 81% dissolution observed in patients with stones up to 5 mm 1
- Patients with calcified gallstones, stones >20 mm in diameter, or who develop stone calcification or gallbladder nonvisualization during treatment rarely achieve dissolution 1
- Age, sex, weight, degree of obesity, and serum cholesterol level are not related to the chance of stone dissolution 1
Duration of Treatment and Recurrence
- Treatment will typically be required for 1-2 years in most patients 3
- Stone recurrence after dissolution has been observed in up to 50% of patients within 5 years of complete stone dissolution 1
- Serial ultrasonographic examinations should be obtained to monitor for recurrence of stones 1
Safety Considerations
- UDCA treatment is generally well-tolerated with minimal adverse effects 4
- Unlike chenodeoxycholic acid, UDCA does not appear to cause significant increases in lithocholic acid, which can be hepatotoxic 1
- Most biliary symptoms tend to disappear within 3 months of starting therapy 5
While higher doses of UDCA (15-20 mg/kg/day) are used for other conditions like primary biliary cholangitis and primary sclerosing cholangitis, the evidence specifically for gallstone dissolution supports the 8-10 mg/kg/day dosage as optimal for efficacy and safety 1, 2.