Hyperalgesia in opioid-managed chronic pain and opioid-dependent patients.

Abstract This observational study aimed to determine whether pain sensitivity in patients with noncancer chronic pain, taking either methadone or morphine, is similar to patients maintained on methadone for dependence therapy, compared with a control group. Nociceptive thresholds were measured on a single occasion with von Frey hairs, electrical stimulation, and cold pressor tests. In all subjects receiving methadone or morphine, nociceptive testing occurred just before a scheduled dose. Cold pressor tolerance values in patients with noncancer, chronic pain, treated with morphine and methadone, were 18.1 ± 2.6 seconds (mean ± SEM) and 19.7 ± 2.3 seconds, respectively; in methadone-maintained subjects it was 18.9 ± 1.9 seconds, with all values being significantly ( P Perspective This article presents an observational study whereby the pain sensitivity of patients with chronic pain managed with opioids and opioid-maintained patients were compared with opioid-naive patients. The results suggest that opioid use may contribute to an increase in the sensitivity to certain pain experimental stimuli.