"The Effect of Memantine on the Prevention and Amelioration of Paclitaxel-induced Toxicity in Breast Cancer Patients"

Cancer is currently a leading cause of morbidity and mortality worldwide. Chemotherapeutic agents, despite being effective in arresting the progression of cancer by targeting and eliminating rapidly dividing cancer cells, are associated with various adverse effects. Chemotherapy-induced peripheral neuropathy (CIPN) is a serious clinical adverse effect of certain chemotherapeutic agents. For many patients, CIPN symptoms could be severe, disabling, and significantly impairing the activities of daily living (ADL) and diminishing the quality of life (QoL). Paclitaxel-induced peripheral neuropathy may affect up to 97% of paclitaxel-treated patients and become chronic in more than 60% of cases. The initial symptoms of paclitaxel-induced peripheral neuropathy (PIPN) include numbness, tingling, and allodynia (painful sensations in response to normally non-painful stimuli) that can be manifested in the patient's fingers and toes within 24-72 h post-injection. These symptoms may later progress to affect the patient's lower leg and wrists in a "glove and stocking" pattern. Symptoms typically begin distally and continue proximally as the situation worsens. Memantine is a non-competitive NMDA receptor antagonist that inhibits the prolonged influx of Ca2+, responsible for neuronal excitotoxicity while maintaining the physiological NMDA receptor's function and avoiding psychotropic adverse events. Although memantine has been the main treatment option for moderate and severe Alzheimer's disease in the last two decades, numerous studies have investigated its other potential uses. Some studies showed that memantine diminished chronic pain in complex regional pain syndrome, phantom limb pain, and fibromyalgia. Most in vivo and in vitro studies attributed the neuroprotective effects of memantine to the blockade of NMDA receptors on neurons as well as inhibition of microglia activation with subsequent reduction of pro-inflammatory mediators' production such as extracellular superoxide anion, intracellular ROS, nitric oxide, prostaglandin E2, and TNF-α, and stimulation of neurotrophic factor release from astroglia.