Ropivacaine for postoperative epidural analgesia

Ropivacaine is a long-acting local anesthetic that has lower toxicity than bupivacaine and causes less motor block when given via the epidural route in low concentrations. This makes it a potentially useful drug for postoperative epidural analgesia. Studies with epidural infusions of plain ropivacaine for 24 to 72 hours have shown that a large proportion of patients (up to 50%) required supplemental analgesics or were withdrawn from the study because of inadequate analgesia. This is not surprising and is consistent with earlier experience with bupivacaine because clinical experience shows more rapid segmental regression with ropivacaine than bupivacaine; however, when combined with fentanyl (2 to 4 μg/mL), ropivacaine 0.2% provides a similar quality of analgesia to bupivacaine (0.1% to 0.2%) with fentanyl (2 to 4 μg/mL), although there are few direct comparisons. The use of patient-controlled epidural analgesia with ropivacaine also is effective provided it is combined with an opioid. Initial studies with levobupivacaine show a similar need for admixture with adjuvants (eg, fentanyl) for effective postoperative analgesia. The incidence of motor block in the lower limbs is low with thoracic epidural infusions, and no difference has been consistently shown between ropivacaine and bupivacaine. There is evidence, however, that with lumbar epidural infusions, less motor block occurs in patients receiving ropivacaine than similar concentrations of bupivacaine. Acute toxicity is highly unusual in the postoperative setting. Both ropivacaine and bupivacaine show no significant increase in free plasma levels during prolonged (up to 72 hours) epidural infusion. There is a theoretical advantage of ropivacaine, and possibly levobupivacaine, in the circumstance of massive epidural overdose because of more rapid block regression than bupivacaine and less systemic toxicity. Copyright © 2001 by W.B. Saunders Company