Inhibition of bile salt excretion and bile flow by spasmolytic drugs. An additional therapeutic effect in the treatment of biliary colics?

The influence of the spasmolytic drugs hyoscin-N-butylbromide (HBB, Buscopan) and Extractum opii (E. opii) on bile flow, bile salt and bilirubin excretion is investigated in the cholecystectomized, unanaesthetized pig and compared with the results after acute, quantitative interruption of the enterohepatic circulation (EHC) by biliary drainage. The results demonstrate that HBB and E. opii induce a significant decrease in bile flow and bile salt excretion. A further analysis suggests that this effect is due to an inhibition of intestinal motility and transit time, followed by a delay of the EHC of bile salts with a decrease in biliary bile salt excretion and bile salt dependent bile flow. The results point out a second mechanism that might be responsible for the effectiveness of spasmolytic drugs in the treatment of biliary colics: the lowering of intraluminal pressure by inhibition of bile salt dependent bile flow.