The effect of memantine

In addition to medications that are called "memantine," Axura and Ebixa are also authorized for the treatment of Alzheimer’s in Germany. They all contain the active ingredient memantine. This drug is approved for people who have moderate to severe Alzheimer’s. It is believed to help prevent excess levels of the substance glutamate from damaging the brain. Glutamate is a substance responsible for carrying nerve signals. Experiments on animals suggest that people who have developed Alzheimer’s might also have too much glutamate in their brain. Memantine is meant to prevent excess glutamate from killing the nerve cells, without disturbing the normal transmission of nerve signals.

Tested in good-quality studies

Several systematic reviews looked into whether people who have Alzheimer's can benefit from memantine. The researchers were interested in several things, including whether the drugs improved mental performance, relieved mental health problems or made it easier to manage everyday tasks. They also looked into whether the medication influenced the need for care. A further aim of their analysis was to determine whether memantine is more or less effective than other medicines like Ginkgo-based products or cholinesterase inhibitors.

The studies compared memantine with a placebo (fake drug), with other medications, or with non-drug treatments. Quite a lot of good-quality studies are available, so it's possible to properly assess the short-term advantages and disadvantages. The benefit after several years of use has not yet been studied.

Memantine can somewhat delay the worsening of some abilities

The ability to manage practical activities of daily life – such as brushing your teeth, getting dressed or taking a bus or tram – worsened over the course of the study in all participants. But the studies suggest that memantine can delay this process.

They also show that memantine can somewhat delay the decline in mental performance (such as learning or remembering something, for example) a little longer. Memantine was able to delay the worsening of mental performance over a period of six months in about 1 out of 10 people. The studies also suggest that it can relieve severe restlessness and improve mood.

There is no information in these studies about whether memantine influences how long people with Alzheimer's can still be cared for at home, though. There is also no evidence that this treatment helps to lessen the burden on family members or loved ones, for example by lowering the need for care or reducing emotional stress. The studies didn't provide much data about the affected people's quality of life, either.

The effect of memantine didn't depend on the study participants' age, sex, or severity of disease.

Side effects

People who took memantine didn't drop out of studies early due to side effects more often than people who took a placebo. This is a sign that memantine was well-tolerated. But it cann't be ruled out that it might sometimes cause side effects like tiredness or dizziness. Also, the participants were in relatively good health, aside from having Alzheimer’s disease. So it isn't clear how well memantine would be tolerated by people who are also taking medication for other conditions.

Unanswered questions

Since none of the studies lasted longer than twelve months, the consequences of long-term treatment with memantine remain unclear. It is also difficult to judge how memantine compares with other medications or non-drug treatments for Alzheimer's.

Sources

• Fink HA, Linskens EJ, MacDonald R et al. Benefits and Harms of Prescription Drugs and Supplements for Treatment of Clinical Alzheimer-Type Dementia. Ann Intern Med 2020; 172(10): 656-668. [PubMed: 32340037]
• Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Memantine in Alzheimer's disease: Final report; commission A05-19C. 2009.
• Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Responder analyses for memantine in Alzheimer's disease: Rapid Report; commission A10-06. 2011.
• Matsunaga S, Kishi T, Iwata N. Memantine monotherapy for Alzheimer's disease: a systematic review and meta-analysis. PLoS One 2015; 10(4): e0123289. [PMC free article: PMC4393306] [PubMed: 25860130]
• McShane R, Westby MJ, Roberts E et al. Memantine for dementia. Cochrane Database Syst Rev 2019; (3): CD003154. [PMC free article: PMC6425228] [PubMed: 30891742]

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