Evidence for opioid variability, Part 1: A biological perspective.

The interplay of biological and pyschosocial factors explain the unique individual differences in opioid requirements that occur among postoperative patients. Nurses must be familiar with the physiologic mechanisms that influence opioid analgesia. Despite growing evidence that doses of opioid analgesics needed to achieve pain relief vary significantly from patient to patient, standardized dosing regimens continue to drive administration of medications for postoperative pain. In this article, evidence-based literature related to the biologic factors that contribute to differences in responses to opioid medication will be examined. Content will assist the Perioperative Nurse to recognize the pharmacology of opioid analgesics and the scientific basis for differences in the body's ability to metabolize and excrete opioids. These differences include age, gender, genetic predisposition, type of surgical procedure, preexisting pain, and prior or concurrent opioid use. Specific terms are introduced and defined to increase understanding of opioid variability.

Evidence for opioid variability, Part 2: Psychosocial influences.

There is substantial evidence to show that certain biological and psychosocial factors affect opioid requirements after surgery. In fact, evidence suggests that individuals are much more likely to be different rather than similar in how they sense pain, react to it and respond to therapy. In an earlier report (Seminars in Perioperative Nursing 10:3-16, 2001), we examined research related to the biological differences that explain variability in postoperative opioid use and defined relevant terminology. Here, we discuss the evidence that links psychosocial experiences to postoperative analgesic outcomes and pain, which include psychological states of patients, cultural influences and attitudes, and beliefs and biases held by both patients and health professionals. Content will assist perioperative nurses to understand the characteristics of their patients and circumstances that place patients at risk for needing increased analgesia or experiencing poor pain control. As perioperative nurses strive to integrate research into practice, it will be important to examine the results of research studies and to determine the usefulness of this information in developing individualized plans for postoperative pain management.