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OPIOID SIDE EFFECTS PROFILES: ASSOCIATIONS WITH ANALGESIC RESPONSE AND PSYCHOLOGICAL FACTORS Hastie, Barbara, PhD; Riley, Joseph, PhD; Glover, Toni, MS, RN; Staud, Roland, MD; Fillingim, Roger, PhD; Public Health Service & Research, College of Dentistry, University of Florida. BACKGROUND: Opioid Side Effects (SE) impact individuals response and adherence to pain treatment, but little is known about symptom clusters and their relationship to gender, opioid type, analgesic response and the role of psychological dimensions. This study evaluated the influences of affective factors, gender, and analgesic response to Morphine (mu-opioid) and Pentazocine (mixed action opioid) and associations with SE cluster profile. METHODS: 213 healthy subjects (57.7% female) completed psychological instruments (CSQ-R, PANAS, PILL, and Kohn Reactivity Scale) and underwent psychophysical testing, including thermal, ischemic and pressure pain assessments measuring tolerance, threshold, pain intensity/unpleasantness prior to and 30 minutes following drug administration. Subjects were randomly assigned to receive drug or saline on separate days. Subjects were grouped into SE profiles using cluster analysis and analgesic indexes (AIs) were calculated from change scores. ANOVAs were performed using gender, drug, and profile group (PG) as factors to test for differences on AIs and psychological measures. RESULTS: Cluster analysis identified three groups: Low SE (LSE); Euphoric/Mild confusion/Dullness (EMD); High Somatic/Confusion (HSC). Analyses revealed the EMD group had the greatest pain reduction and HSC had the least (Ps<.05). For psychological factors, HSC was highest on the KRS, lowest on PANAS-positive and CSQ-CSS whereas EMD was highest on PANAS-positive, PILL-no pain, CSQ-CSS; LSE had lowest PANAS negative (Ps<.05). Gender did not interact with PG; however, main effects for side effects emerged with Pentazocine but not Morphine. CONCLUSIONS: This is the first study to examine the relationship between SE profiles, analgesic response, gender, and psychological factors of healthy adults. Side effects are associated with some but not all measures of pain reduction and greater symptoms are generally associated with pre-existing psychological characteristics. Gender did not interact with profile group although opioid type influenced side effects. Further research is needed to elucidate these associations in clinical populations. |