Side-effects of epidural infusions of opioid bupivacaine mixtures

The incidence of side-effects occurring with epidural diamorphine (0.05 mg. ml(-1)), fentanyl (2.0 mu g.ml(-1)), methadone (0.1 mg.ml(-1)), morphine (0 .05 mg.ml(-1)) and pethidine (1.0 mg.ml(-1)) used by infusion in combinatio n with bupivacaine has been compared. One hundred and sixty patients were s tudied, 32 receiving each opioid. The incidence of nausea and vomiting was significantly greater with morphine than fentanyl (p = 0.0097) and pethidin e (p = 0.0021). The incidence of pruritis tvas significantly greater with m orphine and diamorphine than with methadone (p = 0.012) and pethidine (p = 0.027). Morphine was also associated with a significantly greater incidence of urinary retention than pethidine (p = 0.012) and methadone (p = 0.025).