Memantine Basics (Brand Name Namenda)
In June 2000, Memantine was explored for use in the United States for the treatment of Alzheimer's disease, neuropathic pain and AIDS-related dementia. In May 2002, Merz announced that Memantine (Ebixaš) was approved by the regulatory authorities in the European Union for the treatment of Alzheimer's disease. In October 2003, Forest announced that it received FDA approval of Memantine (Namenda) for the treatment of moderate-to-severe Alzheimer's disease. Namenda became available for patients in the United States starting in January 2004.
The makers of the drug report make these sample comments: Memantine is the first and only representative of a new class of Alzheimer drugs – a moderate affinity NMDA-receptor antagonist [blocker] ...
Efficacy of Memantine
Clinical data on memantine show
Memantine produces symptomatic improvements in learning under conditions of tonic NMDA receptor activation in Alzheimer's disease. In contrast to first generation therapies, memantine is likely to show neuroprotective effects at concentrations used in the treatment of Alzheimer's disease and to slow down disease progression. Read more in the chapters Clinical Studies and Preclinical Data.
Dosage of memantine
The daily dose of memantine is 20 mg.
Tolerability of memantine
Find more detailed information in the summary of Product Characteristics.
One AntiAging Organization Offers These Sample Comments:
It is thought that glutamate – the brain's primary excitatory neurotransmitter – plays a significant role in the neuronal cell death that is common to all neurodegenerative diseases. As neurons are damaged – in Alzheimer's, for example, by the deposition of amyloid – that damage leads to an excess release of glutamate, which neuroscientists refer to as 'overexcitation'. By blocking the action of glutamate at NMDA receptors, Memantine directly short-circuits the overexcitation.
Memantine's unique way of working
The majority of current drugs that treat Alzheimer's disease, such as Galantamine, do so by inhibiting an enzyme called acetylcholinesterase. This enzyme breaks down the brain neurotransmitter- acetylcholine. It is acetylcholine that is badly affected in Alzheimer's patients.
But Memantine works very differently. It appears to protect the brain's nerve cells against glutamate, a messenger chemical released in excess amounts by cells damaged by Alzheimer's disease or certain other neurological disorders. When glutamate binds to N-methyl-D-aspartate (NMDA) receptors, this attachment permits calcium to flow freely into the cell. Sustained elevation of glutamate leads to chronic overexposure to calcium, which in turn leads to cell degeneration. Memantine may prevent this destructive sequence by filling the NMDA receptor sites.
Memantine and the premature aging of the brain
Although Memantine has been in use in Germany for nearly 10-years, it is only recent clinical trials that have highlighted many of its unique properties, particularly for its use in age-related dementia.
As Memantine offers Alzheimer's sufferers improvements in memory, attention, reason, language and the ability to perform simple tasks, there are potential benefits for non-Alzheimer's sufferers too.
Over stimulation of NMDA receptors is referred to as excitotoxicity. Biochemist James South MA, stated in the Fall 2001 issue of the IAS Anti-Aging Bulletin, that there are daily factors in everyday lives, many of them present in certain diets, that cause over excitation of NMDA receptors. Most notably these are some artificial sweeteners, flavor enhancers, (especially MSG) and even hydrolyzed vegetable proteins.
Particular caution are listed for these people and situations: If you have a history of epileptic seizures
If you have recently suffered a myocardial infarction (heart attack) or if you suffer from under-compensated cardiac insufficiency or untreated high blood pressure.Under these circumstances treatment must be carefully monitored and the clinical use of memantine regularly re-evaluated by your doctor.
If you suffer from moderately severe kidney dysfunction, your doctor should carefully monitor your kidney function and adapt the memantin dosage appropriately. The use of memantin is not recommended for patients with severe kidney dysfunction.
Simultaneous use of medications with active ingredients such as amantadine, ketamine, dextromethorphane as well as other NMDA antagonists should be avoided.
The use of memantine is not recommended for children or anyone under the age of 18.