Hepatobiliary disposition of vecuronium bromide in man

The plasma and bile concentrations, the biliary excretion and the neuromuscular blocking effect of vecuronium bromide were studied during surgery in 13 patients who had received 150 micrograms kg-1 i.v. The amount of vecuronium in liver biopsies taken after i.v injection was measured in a separate group of six patients. Vecuronium appeared early in the bile, in concentrations that were 30-50 times greater than those in the plasma. On the basis of the measured amount of vecuronium excreted in the bile, together with the accepted average daily bile flow, it was estimated that more than 40% of vecuronium was excreted in the bile in 24 h. Liver biopsies indicated that the liver may contain more than 50% of the i.v. dose 30 min after injection. The large distribution of vecuronium into the liver may account for the initial rapid decline in vecuronium plasma concentration and its relatively short duration of action. In this study, neuromuscular blockade was prolonged, possibly as a result of interference, by surgical manipulation, with the rapid hepatic uptake of vecuronium.