Ropivacaine for obstetric use

Abstract

Ropivacaine is a new local anesthetic similar to bupivacaine but with a lower systemic toxicity and a greater sensory-motor separation that have been established clearly in in vitro, animal, and human studies. Although median effective-dose studies in laboring women have suggested that ropivacaine is approximately 40% less potent when compared with bupivacaine, this difference is not confirmed in obstetric studies aimed at providing adequate pain relief in all parturients. These latter studies found that equal doses of ropivacaine and bupivacaine provided similar analgesia of similar duration, suggesting equipotency with respect to sensory blockade in the obstetric population. In obstetrics, the increased safety profile makes ropivacaine a better choice than bupivacaine for cesarean section with epidural anesthesia in case of an accidental intravascular injection. The greater sensory-motor separation is advantageous in epidural labor analgesia because there are clear indications that ropivacaine is associated with a lower incidence of instrumental deliveries when compared with bupivacaine and because the reduction in motor block itself is a distinct advantage in terms of patient comfort. Based on these observations, ropivacaine is, at present, the drug of first choice in obstetrics. Copyright © 2001 by W.B. Saunders Company