Nonopioid analgesic pipeline: Pharmacology, safety, tolerability, and potential advantages over established agents

BackgroundThe currently available nonopioid analgesics to treat chronic pain have limited efficacy, end-organ consequences, and dose-limiting adverse effects. In this article, the pharmacodynamics, pharmacokinetics, indications, and side effects of the following newer nonopioid agents are discussed: transdermal bupivicaine, milnacipran, lacosamide, and capsaicin. Moreover, the efficacy of these medications is compared with that of the established agents.MethodsTo determine the efficacy of the newer agents (as mentioned above), literature review of randomized, controlled trials, Cochrane database reviews, clinical trials, and pharmaceutical data were performed. Pharmacokinetics, indications, and side effects of these medications were reviewed. Outcome measures focusing on improvement in severity of pain, quality of life, and occurrence of adverse events were also assessed.ResultsThe newer agents do provide clinicians with new nonopioid options in the treatment of chronic pain. They especially have a role in the challenging treatment of chronic neuropathic pain. These agents still have significant associated adverse effects that clinicians should be familiar with prior to initiation of therapy.ConclusionsRandomized, controlled, blinded, head-to-head studies of the newer versus the established agents still need to be published. The results of the current clinical trials of these newer agents suggest that they may provide additional pain relief and possible improvement in quality of life above that received by current established agents.