Opioid Induced Hyperalgesia with Intrathecal Infusion of High‐Dose Fentanyl

INTRODUCTION: Despite being reported since 1943 as well as being the subject of a large body of literature since that time, no consensus has been reached regarding the etiology of opioid induced hyperalgesia (OIH). It is often described as a paradoxical increased pain response to noxious stimuli due to increased sensitization or an acute tolerance to opioids. CASE: We report the case of a 60 year old patient on chronic Intrathecal combined fentanyl and Bupivacaine who had worsening pain with increasing doses and improved after weaning off intrathecal opioids. CONCLUSION: OIH has been described in various settings including patients on methadone maintenance therapy, perioperative opioid administration, cancer patients on opioids, and healthy volunteers who are acutely exposed to opioids, including high dose intrathecal opioids such as Morphine and Sufentanil. To our knowledge, no cases of opioid induced hyperalgesia was previously reported in the case of intrathecal Fentanyl.