Gallstone dissolution rate during chenic acid therapy. Effect of bedtime administration plus low cholesterol diet.

We have studied the dissolution rate of radiolucent gallstones from validated measurements of gallstone area derived from standardized oral cholecystography in 48 patients receiving chenodeoxycholic (chenic) acid, 15 mg/kg/day. Patients were matched in pairs according to gallstone size and randomly allocated to one of two treatment groups. Group A was given chenic acid in three divided doses at mealtimes with an unrestricted diet (the conventional regimen), and group B was given bedtime chenic acid with a low cholesterol diet. In the 24 matched pairs, the mean reduction in gallstone area at 6 months on regimen A was 36% and on B 60%. Median reductions in area were 20% and 57%, respectively (P less than 0.02). Of these matched pairs, 20 were followed at 6 month intervals for 42 months. There was a significant correlation between percentage reduction in gallstone area at 6 months and length of treatment necessary for complete dissolution (P less than 0.001). Fifty percent achieved complete dissolution by 30 months on regimen A, and by 12 months on regimen B (NS). We conclude that gallstone dissolution rate during chenic acid treatment is approximately doubled by bedtime administration plus a low cholesterol diet, thus reducing the duration and cost of treatment.