Skip to Main Content

++

Newer Amide Local Anesthetics: Introduction

++

The use of regional anesthesia has been increasing not only in obstetrics, where it is the predominant anesthetic technique used, but also during surgery and for acute postoperative pain management. This has been partly due to the safety of regional anesthesia because of better injection techniques and equipment, increased attention to detecting (preventing) misplaced injection, greater vigilance/monitoring, and the introduction of newer long-acting amide local anesthetics. The increasing demand for regional anesthesia is nowhere more true than in obstetric anesthesia, where local anesthetics have become the most frequently administered drugs for obstetric pain relief or cesarean delivery. When injected epidurally or intrathecally, local anesthetics provide effective labor analgesia that is superior to that of systemic opioids and without the attendant risks of maternal sedation and neonatal depression. Regional anesthesia is now the most frequently used technique for cesarean section delivery in the U.S.1

++

Historical Perspective

++

Why the need for new amide local anesthetics? The answer is partly related to the history of bupivacaine use, particularly in North America and Europe. After its introduction into clinical practice, bupivacaine quickly became very popular for several reasons, particularly for use in obstetrics. It has a longer duration of action than 2-chloroprocaine and lidocaine and thus requires less frequent supplemental doses, a feature that is less important now with the widespread use of continuous epidural infusion techniques. More important and in contrast to other local anesthetics, bupivacaine has a motor-sparing effect; it produces less motor block for a comparable degree of sensory analgesia. This is particularly true at the low concentrations used for labor epidural analgesia and acute postoperative pain management. Furthermore, bupivacaine has excellent compatibility with neuraxial opioids, and this allows for concentrations as low as 0.03% and 0.04% bupivacaine to be used successfully so that many patients are pain-free and even able to ambulate during labor or with regional analgesia after surgery. Less motor block also improves expulsive efforts during the second stage of labor and may reduce the need for an instrumental vaginal or abdominal delivery.2 The ability of bupivacaine to provide good sensory analgesia with little motor block is essential for management of postoperative, during which early mobilization may decrease the risk of deep venous thrombosis and result in better respiratory mechanics. Nonetheless, despite its many advantages, there have been some concerns regarding bupivacaine, particularly in obstetric anesthesia.

++
Favorite Table | Print
Clinical Pearls
  • In contrast to other shorter-acting amide local anesthetics, bupivacaine, levobupivacaine, and ropivacaine have a motor-sparing effect; they produce less motor block for a comparable degree of sensory analgesia.
  • This feature is particularly true at the low concentrations used for labor epidural analgesia and acute postoperative pain management.
++

Clinical experience has been that cardiac arrest after unexpected intravascular injection of clinical doses of local anesthetics could be prevented by prompt oxygenation, ventilation, and, if necessary, cardiovascular support. ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.