The effect of epinephrine in local anaesthetic on epidural morphine-induced pruritus.

The severity of epidural morphine-induced pruritus was evaluated following the addition of epinephrine to the local anaesthetic solution used for Caesarean section anaesthesia. The local anaesthetic solutions used were: Group I--0.5 per cent bupivacaine plain--20 patients. Group II--0.5 per cent bupivacaine with 1:400,000 epinephrine--25 patients. Group III--0.5 per cent bupivacaine with 1:200,000 epinephrine for the 3 ml "test dose" followed by 0.5 per cent bupivacaine plain for anaesthesia--21 patients. The severity of the pruritus, as measured by completion of a visual analogue "itch scale" and by requests for medication for pruritus, was statistically significantly greater in both groups in which epinephrine was added. This effect was not dose-related, as the "test dose" group (15 micrograms epinephrine) experienced the most severe itch. This latter difference was also statistically significant (p less than 0.05).