Methadone Induced Hyperalgesia: Is It Possible? (775)

Abstract

1.Recognition of opioid induced hyperalgesia (OIH) as a possible complication of pain management with opioids.Review of opioids that can induce OIH.2.Review of treatment options available for OIH. Opioid induced hyperalgesia (OIH) is characterized by paradoxical worsening of pain despite escalating doses of opioids. It can pose a significant challenge to pain management. The management of OIH usually requires decreasing the dose of opiates, opiate rotation and the use of non-opioids. Although OIH has been generally recognized in patients with chronic use of morphine or hydromorphone, we present a case of OIH most likely induced by methadone. The patient is a 64 year-old male with severe COPD and a remote history of polysubstance abuse, hospitalized for pneumonia and chronic low back pain secondary to osteoarthritis. His past medical history was significant for type 2 diabetes mellitus, chronic kidney disease and hepatitis C. While in the hospital, he sustained a mechanical fall resulting in left tibial and fibular fractures, treated conservatively with a long cast and non-weight bearing status. Prior to admission he was taking acetaminophen/codeine for low back pain. After the fracture, he was tried on various opioid regimens to control a flare-up of the low back pain and his painful fractured leg. Due to uncontrolled back and leg pain, methadone and hydromorphone were initiated. While on methadone 5 mg orally three times a day and hydromorphone 1 mg orally every 4 hours for breakthrough pain for one week, he developed severe pain in the cervical spine, low back, hips and left lower leg. He also developed mild confusion and myoclonus which were thought to be secondary to opioids. The dose of methadone was decreased to 2.5 mg twice a day and within 48hrs he had a remarkable improvement in his pain, and his confusion and myoclonus resolved. The remarkable improvement in pain control following a reduction the in dose of methadone suggests the clinical scenario of OIH induced by methadone.