[Dissolution of gallstones based on 6 months treatment with a single daily dose of ursodeoxycholic acid]

51 patients with radiolucent gallstones of diameter less than or equal to 15 mm were treated for 6 months with a new form of ursodeoxycholic acid (UDCA) in a single dose of 450 mg at bedtime. This new form has 3 components with fractionate liberation. The rate of partial and complete dissolution after 6 months was 63.4%, reaching 85% for gallstones of less than 5 mm diameter. The results show that a single dose of 450 mg UDCA at bedtime is as effective as UDCA at mealtimes in the dissolution of radiolucent gallstones. Administration of the drug once a day should be more acceptable to patients.