Chronic non-cancer pain and the long-term efficacy and safety of opioids: Some blind men and an elephant?

Background The use of opioids for chronic non-cancer pain (CNCP) remains very controversial. There are a number of randomized controlled trials (RCTs) showing efficacy and safety in the short-term, but long-term data are limited. Methods This article contains 10 case reports (followed to 2011) that were selected from a survey of 84 patients with intractable CNCP treated with opioids and followed every 3 months now for a median of 10 years. The previous published survey of this group reported outcomes of pain severity, adverse effects, pain relief, satisfaction, mood, problematic opioid use, tolerance, physical dependency, functional status, health-related quality of life (HRQL), immune status and sexual function. The outcome measures for that study included a numerical rating scale (NRS) for pain, Hospital Anxiety and Depression Scale (HADS), the Brief Pain Inventory Interference Scale (BPI-I), the Pain Disability Index (PDI), and for Health Related Quality of Life (HRQL) the Short Form Health Survey 12 version 2 (SF12v2). These selected patient reports were chosen to illustrate some important aspects of the diagnostic categories of CNCP, the opioids and doses used, particular issues (concurrent addiction history, bipolar disorder, and combination therapy), disease-specific and other outcomes (pain severity and relief, adverse effects, mood, function) and duration of follow-up with complex pain problems. Results Opioids were found to be safe and effective in the long-term for these particular patients, as well as in the larger group from which they originate. Most patients in the total sample reported 50% or greater relief and a moderate improvement in disability. Scores for functional status and HRQL were not severely affected (PDI and BPI-I ratings moderate or less and SF12v2 slightly below normative values for age). Problematic use, tolerance, and serious adverse effects including constipation were not major issues. Conclusion These 10 reports of patients with intractable CNCP treated with opioids with some success over many years put a face on some of the participants in the larger survey of 84 suggesting that this approach is effective and safe for some patients over many years. Implications These data may not be generalizable to a larger population of patients with CNCP because of the probable selection of patients who benefit and who do not have intolerable adverse effects.