Opioid therapy for chronic non cancer pain: how to make the right choice

The WHO analgesic ladder provides an approach for managing patients with malignant pain. In clinical practice, this ladder is often applied to nonmalignant chronic pain, although its application in this setting is limited by its original design for a malignant pain model and omission of pain etiology and biological mechanism in symptom assessment. The WHO analgesic ladder directs therapy based on pain severity and persistence, with drug therapy recommendations which extends from nonopioids (e.g., NSAIDs and paracetamol) for mild pain followed by weak (e.g., codeine) and strong opioids (e.g., morphine) for moderate to severe pain, and adjuvant therapies if appropriate. However, a Cochrane analysis found long-term opioid therapy was either ineffective or poorly tolerated by a third of patients with nonmalignant chronic pain. This lack of evidence for long-term therapy is also problematic for nonopioid therapy. Short-term opioid therapy has been associated with adverse effects (e.g., nausea, constipation, somnolence, dizziness and pruritus) in 50-80 percent of patients. Additional concern are tolerance and addiction to opioids during long- term opioid therapy. This short review will highlight the issues of chronic opioid therapy and propose how to optimize it.