Abstract
A single oral dose of the diuretic chlorthalidone (100 or 200 mg) was given to six cholecystectomized patients with Tโtube drainage of the common bile duct, and the 24 h bile and urine were collected during 3โ7 days. Urinary recovery of chlorthalidone was 23โ27 per cent of the dose, which is in the range of that in healthy volunteers. Chlorthalidone concentration in bile was 11โ44 times lower than urine concentration in corresponding periods, and biliary recovery was only 0ยท6โ1ยท4 per cent of the dose. When compared from equal periods of sampling of bile and urine, the same relative amount of drug was found in bile, whether the 100 or 200 mg dose had been given (viz., a fraction of 2ยท5โ4ยท7 per cent and 2ยท5โ5ยท7 per cent of corresponding urinary amounts respectively). It was concluded that excretion into bile constitutes only a minor route of elimination for unchanged chlorthalidone. Bile samples treated with glucuronidase and sulphatase showed no increase of chlorthalidone concentration. The open acid analogue of chlorthalidone, 3โ(4โchloroโ3โsulphamoylbenzoyl)โbenzoic acid, was apparently not formed as a human metabolite, as evidenced by gas chromatographic analysis of both urine and bile.