Pharmacotherapy of low back pain: targeting nociceptive and neuropathic pain components.

AIM: To review pharmacological management of chronic low back pain (LBP), with respect to management of nociceptive and neuropathic components.
METHODS: Studies were identified by a PubMed search of English-language papers from the last 10  years, with additional hand searches of relevant reviews. DISCUSSION: Paracetamol, non-steroidal anti-inflammatory drugs and cyclo-oxygenase-2 inhibitors target the nociceptive component of chronic LBP, and do not affect neuropathic pain mechanisms. Antidepressants target the neuropathic component of chronic LBP; however, conflicting efficacy results have been reported. Opioids target both nociceptive and to a lesser extent neuropathic pain. They are effective in chronic LBP, but many patients require higher doses or combination treatment. The long-term efficacy of opioids in chronic LBP has been questioned because of the absence of high-quality data and concerns regarding tolerability and dependence. The topical preparation lidocaine 5% plaster, indicated in post-herpetic neuralgia, is effective in localized neuropathic pain in patients with chronic LBP. Pregabalin is ineffective as monotherapy for chronic LBP but is effective when combined with celecoxib or opioids. Muscle relaxant monotherapy is ineffective in chronic LBP. Combination therapy is often necessary in patients with chronic LBP, in order to manage both nociceptive and neuropathic pain components.
CONCLUSION: Chronic LBP often comprises both nociceptive and neuropathic components, therefore a multimodal and individualized treatment approach is necessary. Combining drugs with different mechanisms of action (e.g. an agent with µ-receptor activity plus an agent of a different class) represents a rational approach to management of chronic LBP with both nociceptive and neuropathic components.