The Role of Opioids in Chronic Non-Cancer Pain Management.

Abstract

Chronic pain is prevalent in Asia as well as worldwide, and physicians must carefully consider which pharmacologic or non-pharmacologic analgesic strategy is appropriate based on its availability, adverse effects, abuse liability, potential drug-drug interactions, onset of action, tolerability, cost, and-above all-effectiveness. NSAIDs increase the pain threshold by inhibiting cyclooxygenase (COX) and are the first step of the World Health Organization "pain ladder," but they have been associated with gastrointestinal complications, possible renal failure, and hypertension. Acetaminophen (paracetamol) is an effective pain reliever for mild to moderate pain, but is associated with liver toxicity at high doses. Opioids are effective pharmacologic treatment and standard therapy for moderate to severe cancer pain, but their long-term use for non-cancer pain is controversial. Opioid-associated side effects may be transient, treatable, or treatment limiting. Not all chronic non-cancer pain patients are candidates for opioid therapy, particularly if there are risk factors for misuse or abuse. Combining an opioid and a nonopioid (such as acetaminophen or NSAID) in combination therapy can create synergistic analgesic effect and reduce the patient's total opioid consumption while still achieving good analgesic results. Adjuvant agents such as anticonvulsants or tricyclic antidepressants can be useful to deal with multimechanistic pain, including pain with a neuropathic component, frequently observed in chronic non-cancer pain patients.