Extended-duration agents for perioperative pain management.

Perioperative pain management has drastically evolved over the years to satisfy current unmet needs. Intermittent delivery of drugs has been replaced by continuous delivery systems involving oral, neuraxial, and peripheral nerve block routes of administration. One current standard of perioperative pain management is an epidural injection of an opioid such as morphine, fentanyl, or hydromorphone, with or without the addition of a local anesthetic, such as bupivacaine. Although this method is extremely effective in controlling pain during the most critical 48-hour period postoperatively, it also has its disadvantages. Risks associated with indwelling epidural catheters include infection, adverse effects, and spinal hematoma. The development of extended- and controlled-release drug delivery systems has revolutionized perioperative pain management. This class of drugs comprises MS Contin (Purdue Pharma LP, Stamford, CT), OxyContin (Purdue Pharma LP), Opana ER (Endo Pharmaceuticals, Chadds Ford, PA), and DepoDur (Endo Pharmaceuticals). There are also phase II trials in progress examining controlled-release formulations of local anesthetics. This review discusses extended- and controlled-release agents administered perioperatively.