A cross-over comparison of the effect of morphine, pethidine, pentazocine, and phenazocine on biliary pressure

The effects on biliary pressure of pentazocine, morphine, pethidine, and phenazocine were compared by direct measurement through a `T' tube after choledochotomy. In two within-patient comparisons, the mean increases in biliary pressure following intramuscular morphine were significantly greater than those following pentazocine. When pethidine and phenazocine were compared with pentazocine, the mean increases were lower following pentazocine but not to a statistically significant extent. Pentazocine appears to be the most appropriate strong analgesic in biliary and pancreatic disease.