Chlorpromazine (10 μmol/L) causes a marked increase in portal pressure in perfused rat liver. Simultaneously, oxygen consumption, hepatic clearance of taurocholate and bile flow are diminished. These effects are prevented by the cyclooxygenase inhibitors indomethacin (15 μmol/L), acetylsalicylate (3 mmol/L) or ibuprofen (200 μmol/L). On addition of chlorpromazine the liver releases increased amounts of prostaglandin D2; this increase does not occur in the presence of indomethacin.

At higher concentrations of chlorpromazine (100 μmol/L) the inhibition of taurocholate clearance and bile flow is accompanied by only a moderate increase of portal pressure, and indomethacin is without effect. At this high concentration, substantial cell damage, as indicated by the release of lactate dehydrogenase, is present.

We conclude that arachidonic acid—derived metabolites, notably prostanoids, are involved in the inhibition of bile flow and of taurocholate clearance observed at low concentrations of chlorpromazine. The data suggest that changes in the microcirculation are responsible for the impairment of the liver functions. At higher concentrations of chlorpromazine the cell toxicity of the drug becomes prominent. (HEPATOLOGY 1991;13:216–221).