Common bile duct pressure in dogs after opiate injection--epidural versus intravenous route

The effect on the common bile duct pressure of epidurally injected morphine and fentanyl, was compared with that of intravenous injections of the same drugs in 12 mongrel dogs. Intravenous injection of morphine (0.1 mg X kg-1) or fentanyl (0.01 mg X kg-1) significantly elevated the common bile duct pressure from 10.48 +/- 0.37 to 21.68 +/- 0.33 cm H2O and from 9.66 +/- 0.33 to 14.14 +/- 0.21 cm H2O respectively. These increases occurred within 4-15 minutes after injection and lasted for about 2-3 hours. When the narcotics in identical dosages were injected epidurally, the common bile duct pressures were unchanged during the four hours of investigation. Further studies are planned to determine whether this beneficial effect of epidural narcotics applies also in the human clinical situation.