Which medications are being investigated for the treatment of low back pain (LBP)?

Updated: Aug 22, 2018
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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Answer

The role of inflammation in causing segmental and radicular pain has been reviewed. Cytokines, released by activated macrophages, mast cells, Schwann cells, and microglia, play a major role in nociception and inducing chronic neuropathic pain. [117] Infliximab is a chimeric monoclonal antibody against TNF-α, a cytokine with a known role in eliciting spinal nociception. In a recent study, 10 patients with severe sciatica from disk herniation received intravenous infliximab and were compared with a group who were treated with a periradicular infiltration of saline. The infliximab group showed a more than 75% reduction in pain, and the difference was sustained at 3 months. [118] To date, no published data are available regarding the treatment of mechanical spinal pain or sciatica using etanercept (a TNF-α blocker) andanakinra (an IL-1 blocker).

Bisphosphonates, specifically pamidronate, have recently attracted attention as a potential new treatment for mechanical spinal pain involving the diskal and radicular structures. These compounds have demonstrated antinociceptive effects and the capacity to inhibit cytokine release by causing apoptosis of reactive macrophages in experimental animal models. [119, 120, 121, 122, 123, 124, 125]

The cytokine IL-2 possesses antinociceptive (analgesic) effects upon the peripheral and central nervous systems. Preliminary animal work has produced an antinociceptive effect in the spinal dorsal horn via IL-2 gene therapy. [126]

A new chemical compound, designed to be a NO-releasing derivative of gabapentin, was synthesized and designated as NCX8001. This moiety released physiologically relevant active concentrations of NO consequent to experimentally induced sciatic nerve or spinal cord injuries. Observed results included the inhibition of TNF-α and reduced allodynia in the injured rats. [127]

Other potential future treatments include drugs targeted at the nociception (opioid) receptor [128, 129] and the NMDA receptor. NMDA receptor antagonists, such as dextromethorphan (DM), ketamine, and memantine, are thought to be beneficial in cases of chronic pain and long-term opioid therapy. DM has been shown to reduce morphine requirements in randomized controlled trials. [130, 131, 132] Ziconotide is a neuronal calcium channel blocker that affects neurotransmitter release from primary nociceptive afferents at a spinal level. Studies suggest that it has promise for patients with chronic refractory neuropathic pain that is unresponsive to opioids. [133, 134]

Alternative medications (eg, glucosamine) are widely used by patients, but limited data are available to suggest efficacy. Wilkens et al conducted a randomized, placebo-controlled trial in patients with chronic low back pain (LBP) and degenerative lumbar osteoarthritis (OA) (n=250). Patients received either glucosamine (1500 mg/d PO) or placebo for 6 months. Compared with placebo, glucosamine did not reduce pain-related disability after the 6-month intervention and after 1-year follow-up. [135]


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