Antimicrobial activity of bupivacaine and pethidine

The antimicrobial activity of bupivacaine and pethidine in concentrations commonly used in epidural practice was studied by an agar dilution method against ten common micro-organisms. Both drugs showed increasing microbe inhibition with increasing drug concentrations. Bupivacaine at common epidural concentrations inhibited eight of the ten organisms and pethidine inhibited six. These findings confirm previous reports of microbe inhibition by bupivacaine, and in addition demonstrate a similar but slightly lesser activity by pethidine. Although antimicrobial activity of epidural drugs can be regarded as a desirable property, clinical implications of such findings remain unclear.