Ursodeoxycholic acid for the dissolution of radiolucent gall bladder stones.

In a prospective dosage response study of 84 patients with radiolucent gall bladder stones treated with ursodeoxycholic acid (UDCA), a dose of 500 mg daily was as effective as 1,000 mg daily. Complete dissolution of stones was achieved in 9 of 31 patients (29%) treated for at least 6 months with the lower dose, and in 7 of 33 patients (21%) on the higher dose. 4 patients in each group continue on treatment having shown partial gall-stone dissolution. When the two dosage groups were considered together, small stones dissolved more readily than larger ones and, after allowance for stone size, success rates were equal in obese and non-obese patients. Treatment with UDCA was well tolerated and significant adverse effects were not encountered.