Memantine for CRPS

It’s not unusual to discover that drugs developed for one condition are beneficial for another. Good examples are the anticonvulsant drugs Pregabalin and Gabapentin, taken by many people with CRPS. Primarily developed to treat epilepsy, these drugs are also effective in the treatment of neuropathic pain. Similarly, but perhaps less well known, is the possible benefit of the drug Memantine for CRPS.

Memantine for CRPS

In recent years, I’ve read of a growing interest in Memantine, a drug more typically associated with the treatment of moderate to severe Alzheimer’s disease. It’s potential benefit for CRPS lies in the central nervous system (CNS).

The contribution of the CNS in developing neuropathic pain is well-established. Specifically, studies have focused on the role of a group of cells within the CNS with the not-so-catchy name N-methyl-D-aspartate-receptors. Researchers have sought a suitable drug capable of dampening down or blocking the reaction of these cells. Memantine has proved to be effective in doing this.

Clinical studies

In 2007, a very small-scale study of six people with CRPS in one upper limb examined the effect of treating them with Memantine for eight weeks. The results showed that all participants maintained significantly lower pain levels and improved function six months after their treatment.

In addition, brain scanning before treatment revealed changes in a part of the brain called the somatosensory cortex. Following treatment with Memantine, the affected side of the brain returned to a pattern comparable to the unaffected side. Unsurprisingly, researchers recommended a larger-scale study.

MEMOIR study of Memantine for CRPS

It has taken many years, but a large-scale study is now underway. The study, MEMOIR, is led by Professor James McAuley of the University of New South Wales and funded by the Australian government. MEMOIR is a placebo-controlled trial of Memantine in conjunction with Graded Motor Imagery (GRI). It represents the most extensive study yet involving Memantine treatment for CRPS.

Enrolment of participants in the trial began on 12 May 2021. It was anticipated that the enrolment process would continue until early 2023, with data collection continuing until early 2024. The results are still awaited. Watch this space!