Intrathecal bupivacaine for chronic pain: a review of current knowledge

Objective. This article presents an overview of the use of intrathecal bupivacaine (with and without opioid), focusing on laboratory data and clinical use for chronic pain. Some background on epidural use is included to support the intrathecal literature. Materials and Methods. Currently available literature (MEDLINE) regarding the use of intrathecal bupivacaine is reviewed. Prior to presenting the intrathecal bupivacaine data, an overview of data related to bupivacaine stability, microbiology, preclinical toxicology, and pharmacokinetics is presented, along with a brief review of the epidural bupivacaine literature. Results. Based on the current available literature, intrathecal bupivacaine appears to be a safe and acceptable method of treatment for chronic pain in both cancer and noncancer patients. The stability and bacteriologic studies support the use of bupivacaine in external or implantable drug administration devices. Toxicity studies in laboratory animals suggest complications only at plasma levels that would not be seen at clinically relevant doses of intrathecal administration. Bupivacaine is a clinically effective addition to intrathecal opioids. Bupivacaine administration is more effective intrathecally, providing better pain relief than epidural administration. Reports of complications are infrequent. Further studies are needed to define the use of intrathecal bupivacaine and should include long-term safety. Compatibility studies will also be needed when bupivacaine is used in combination with other agents. In addition, outcome studies are needed specifically to differentiate use of intrathecal bupivacaine based on the source and mechanism of pain. Conclusions. While there are few long-term randomized prospective studies at this point, we conclude that intrathecal bupivacaine appears to be a safe and efficacious treatment in both cancer and noncancer pain.