Memantine: Features and application in the management of chronic pain

Chronic pain is very common and affects a large proportion of the population, causing personal distress, decreased function and quality of life, and increasing health care costs. Conditions causing chronic pain are noted as the most common cause of disability and disease burden worldwide. Although a major percentage of the elderly population suffer from chronic pain resulting from musculoskeletal issues such as arthritis and degenerative conditions, chronic pain can also occur after an injury or surgery. The management of chronic pain is often challenging and complex. Therapeutic options are associated with inconsistent results and often only modest improvement in symptoms. There is a need to advance mechanism-based pain understanding leading to diagnosis and management of chronic pain, whenever appropriate. In that direction, it becomes important to consider medications that influence the activity of N-methyl-d-aspartate (NMDA) receptors. NMDA receptors play an important role in the neuroplasticity and neurodegeneration processes, including the generation and sustenance of pain signals. Memantine is an oral NMDA antagonist with a potential for analgesic effect and a reasonably safe profile. In this chapter, we review the background, relevant pharmacology, and preclinical and clinical evidence of its effect on pain. We also provide considerations for clinical use in appropriate populations.