Presented at the 2012 AAPM Annual Meeting « Back

Correlation of Oxycodone Daily Use to Oral Fluid Levels and Its Potential for Detection of Opioid-Induced Hyperalgesia—A Pilot Study

John A. Campa, MD, neuropain@paindiagnosis.net¹, Leah Damiani, PhD¹, (1) University of New Mexico School of Medicine, Albuquerque, New Mexico

Clinicians who treat patients suffering from persistent pain must face the issue of monitoring and regulating medication consumption. Evidence suggests prolonged exposure to opioids may lead to Opioid-Induced Hyperalgesia (OIH), i.e., patient becomes paradoxically more sensitive to pain². Hence, an easily performed lab assay, i.e., oral fluids toxicology (OFT), would be an invaluable clinical tool to assist the clinician in providing safe opioid dosing, while avoiding the induction of OIH. The aim of this study is to assess the reliability of the OFT therapeutic range and its potential for detecting risk for OIH. A 10-month retrospective chart review was performed to study patient oxycodone use and its measurement by OFT. We postulate the OIH threshold to be an opioid daily usage, in morphine sulfate equivalents (MSEq), ≥ 260 mg. Oxycodone MSEq = Daily amount x 1.5. Inclusion criteria: patients taking oxycodone who had OFT. Our data accurately assessed oxycodone use to be within therapeutic range in 13/19 patients. Abnormal results revealed: Probable OIH - 4; At risk for OIH - 1 patient. OFT failed to detect 3/6 patients believed to be at risk for developing OIH, i.e., result less 500 ng./ml. We conclude the OFT therapeutic range accurately detects when an excessive amount of oxycodone is taken, but may fail to identify patients at risk for OIH. Hence, a revised therapeutic range for oxycodone is needed. Additionally, these data suggest patients consuming ≥ 260 mg. MSEq per day are at risk for having or developing OIH. References: 1)Clark JD. Chronic pain prevalence and analgesic prescribing in a general medical population. J Pain Symptom Manage. 2002;23(2):131-137. 2)Angst MS, Clark JD. Oxycodone-induced hyperalgesia: A qualitative systematic review. Anesthesiology. 2006;104(3):570-587. 3)Celerier E, Laulin JP, Corcuff JB, Le Moal M, Simonnet G. Progressive enhancement of delayed hyperalgesia induced by repeated heroin administration: A sensitization process. J Neurosci. 2001;21(11):4074-4080. 4)Carroll IR, Angst MS, Clark JD. Management of perioperative pain in patients chronically consuming Oxycodone. Reg Anesth Pain Med. 2004;29(6):576-591. 5)Wylie FM, Torrance H, Anderson RA, Oliver JS. Drugs in oral fluid part I. validation of an analytical procedure for licit and illicit drugs in oral fluid. Forensic Sci Int. 2005;150(2-3):191-198. 6)Mercadante S, Ferrera P, Villari P, Arcuri E. Hyperalgesia: An emerging iatrogenic syndrome. J Pain Symptom Manage. 2003;26(2):769-775. 7)Guignard B, Bossard AE, Coste C, et al. Acute Oxycodone tolerance: Intraoperative remifentanil increases postoperative pain and morphine requirement. Anesthesiology. 2000;93(2):409-417. 8)Fabregat-Cid G, Asensio-Samper JM, Villanueva-Perez V, Lopez-Alarcon MD, De Andres-Ibanez J. Postoperative pain management for patients who are long-term users of Oxycodone. Rev Esp Anestesiol Reanim. 2011;58(1):25-33. 9)Winek CL, Wahba WW, Winek CL, Jr, Balzer TW. Drug and chemical blood-level data 2001. Forensic Sci Int. 2001;122(2-3):107-123. 10)Campa JA. Narcotic Analgesics – A Reference For the Clinician. San Antonio, TX.: Legacy Publishing SA; 2006

Funding: None