Abstract

The aim of this study was to determine whether bedtime administration and a low cholesterol diet reduce the minimum effective dose of chenodeoxycholic (chenic) acid, defined as the dose giving a mean cholesterol saturation index of 0.8. Dose response studies were carried out in 10 patients with radiolucent gallstones in a functioning gallbladder during three different treatment regimens. On each regimen, all patients received three different doses of chenodeoxycholic acid in random order for one month each. Bedtime chenic acid plus a low cholesterol diet gave the greatest reduction in saturation index. A significant dose/response relationship was found on each regimen. On the conventional regimen of mealtime chenic acid, the minimum effective dose was 14 mg/kg/day; on bedtime chenic acid it was 12.4 mg/kg/day; and on bedtime chenic acid plus low cholesterol diet it was further reduced to 8.4 mg/kg/day (p less than 0.01). There was a dose-related increase in bowel frequency, which was absent at 10.6 mg/kg/day and below. We conclude that administration of chenic acid at bedtime with a low cholesterol diet enables the minimum effective dose for gallstone dissolution to be approximately halved, thus preventing diarrhoea and reducing the cost of treatment.