Spinal Anesthesia Adjuvants

Alan Gonzalez-Cota, M.D.
Anesthesiology Resident
The University of Michigan
Ann Arbor, MI

Raimy Amasha, M.D.
Anesthesiology Resident
The University of Michigan
Ann Arbor, MI

Tony L. Yaksh, Ph.D.
Vice Chairman for Research in Anesthesiology
University of California, San Diego
San Diego, CA

Introduction - TOP

Spinal anesthesia results from injecting local anesthetic directly into the intrathecal space. To improve the spinal anesthetic efficacy, adjuvants from different pharmacological classes of drugs are used to enhance and prolong analgesia, to lower dose requirements, and to reduce dose-dependent side effects. Opioids, first and foremost, have attained an integral role as a spinal anesthetic adjuvant. However, research has supported a number of other non-opioid adjuvants which will be also addressed herein.

Opioid Analgesic Adjuvants - TOP

Opioids are not effective as sole agents in relieving somatic pain of a surgical incision, which is often intense.  Meperidine is the exception to this rule and has both local anesthetic and opioid effects. Opioids are often administered neuraxially in combination with local anesthetics to enhance pain relief. Opioid receptors are located in the dorsal horn of the spinal cord, thus opioids administered into the intrathecal space will inhibit pain signals at this level. Although the onset of analgesia is slower when compared to the parental route; neuraxial dosing requirements are lower, providing a clinical advantage.1

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