Memantine for the treatment of general neuropathic pain: a narrative review

Abstract

A B S T R A C TNeuropathic pain (NP) is difficult to treat and is associated with a decline in quality of life. NP aetiologies are numerous and a number of pathologies display neuropathic characteristics. Of the various N-methyl-D-aspartate antagonists that are alternatives to be recommended in first-line NP treatment, memantine has the safest side-effect profile and has long been approved in Alzheimer's disease. The review covers memantine studies in postherpetic neuralgia, diabetic pain, postoperative pain, complex regional pain syndrome, chronic phantom limb pain, opioidrefractory pain and fibromyalgia. Results were inconclusive because of studies with poor levels of evidence, paucity of trials and small samples. Two recent randomized trials, however, showed significant efficacy of memantine: one demonstrated prophylactic effects against postoperative neuralgia and pain-associated psychological impairment; in the other, memantine improved pain and cognition in fibromyalgia. Both studies found no side effects or adverse events. Given the high rate of therapeutic failure in chronic states, often because of adverse events, the excellent benefit/risk ratio of memantine in these pilot studies encourages further exploration of this drug in NP prevention and in fibromyalgia in larger-scale studies.

Memantine selectively prevented the induction of dynamic allodynia by blocking Kir2.1 channel and inhibiting the activation of microglia in spinal dorsal horn of mice in spared nerve injury model

“…Clinical efficacy of MEM on painful patients also has not been proven, clearly targeting various types of pain. 13 Previous studies mentioned earlier mainly studied the MEM’s effect on punctate mechanical allodynia, and the results remained somewhat contentious. However, the efficacy of MEM on the induction of dynamic mechanical allodynia was less studied at present.…”

Comparison of efficacy of gabapentin and memantine premedication in laparoscopic cholecystectomies for postoperative pain relief – A randomised placebo controlled trial

“…Another reason for the relatively less analgesic effect of memantine might be because of its moderate affinity, strong voltage dependency and rapid unblocking kinetics. [ 9 ] Hence, gabapentin has a better analgesic profile than memantine.…”

A systematic review and meta‐analysis of memantine for the prevention or treatment of chronic pain

“…Although animal studies have demonstrated the effect of memantine on both nociceptive and NeP, clinical studies have mostly focused on NeP conditions. Because NMDA receptors have a central role in NeP, their modification or blockade has continued to interest pain researchers (Aiyer, Mehta, Gungor, & Gulati, ) (Pickering & Morel, ). This is also indicated by the newer molecular entities with specific pharmacological mechanisms, currently under clinical development (Gilron & Dickenson, ).…”

“…Another review attempted to summarize the evidence on memantine alone in NeP. Although this excellent review outlined the background and mechanism of memantine in animal studies, no systematic research was conducted, and studies were not assessed by any specific parameter (Pickering & Morel, ). In light of our observation that pain scores with memantine decreased in patients with chronic pain after surgery, it is interesting that Eisenberg et al postulate the hypothesis that memantine could be more effective at the time of nerve injury rather than later (Eisenberg et al, ).…”