Pain, Opioids and Pro-Inflammatory Immune Responses

Both acute pain and opioid administration have been shown to induce a systemic pro-inflammatory response. However, the presence of these inflammatory responses is unknown in situations where a co-occurrence of pain and opioid administration exists as is the common clinical case of a patient with acute pain and taking opioid analgesics. A patient population for whom the combined effects of pain and opioids on immune function are particularly complex are the estimated 5.2 million Americans aged 12 or older who abuse prescription opioids. Not only are these individuals at risk for poor pain management due to their status as an "addict", but there is good preclinical evidence to suggest that their chronic opioid use brings with it a general state of systemic inflammation, and thus setting the patient up for a unique or enhanced inflammatory response to the combination of acute opioids and pain. To better understand the health implications of treating acute pain with opioids in patients and in particular, those who abuse prescription opioids, inflammatory responses to the main and interaction effects of acute pain and opioid administration will be examined in well-characterized samples of each. Specifically, we will evaluate the inflammatory and cytokine responses to: (1) experimental pain; (2) an acute opioid challenge; and (3) the combination of opioid administration followed by cold-pressor pain, in healthy control subjects and age- and gender-matched prescription opioid abusers.