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Memantine is marketed under the brands Axura and Akatinol by Merz, Namenda  by Forest, Ebixa and Abixa by Lundbeck and Memox by Unipharm. Quote “Despite years of research, whether memantine has any effect in mild to moderate AD is unknown.”

Memantine is the “first in a novel class of Alzheimer's disease medications acting on the glutamatergic system by blocking NMDA glutamate receptors”. In effect it is an NMDA receptor antagonist. But this is not all. Memantine acts as a non-competitive antagonist at the 5HT3 receptor, with a potency similar to that for the NMDA receptor. “The clinical significance of this serotonergic activity in the treatment of Alzheimer's disease is unknown”.

Memantine also acts as a non-competitive antagonist at different neuronal nicotinic acetylcholine receptors (nAChRs) “at potencies possibly similar to the NMDA and 5-HT3 receptors, but this is difficult to ascertain with accuracy because of the rapid desensitization of nAChR responses in experiments”. So it is an anticholinergic. And finally, as if this was not enough, Memantine acts as an agonist at the dopamine D2 receptor. 

Memantine is approved for treatment of moderate to severe Alzheimer's disease, and has now received a limited recommendation by the UK's National Institute for Clinical Excellence for patients who fail other treatment options. Within the new guidance memantine is recommended as an option for managing Alzheimer’s disease for people with: moderate Alzheimer’s disease who are intolerant of or have a contraindication to AChE (acetylcholinesterase) inhibitors or those with severe Alzheimer’s disease.

Memantine is also being tested for generalized anxiety disorder, epilepsy, opioid dependence, systemic lupus erythematosus, depression, obsessive compulsive disorder, Tourette Syndrome, problem gambling, attention-deficit hyperactivity disorder (ADHD), glaucoma, tinnitus, neuropathic pain including Complex Regional Pain Syndrome, pervasive developmental disorders, HIV associated dementia, nystagmus, multiple sclerosis and autism!

Common adverse drug reactions include confusion, dizziness, drowsiness, headache, insomnia, agitation, and/or hallucinations. Less common adverse effects include vomiting, anxiety, hypertonia, cystitis, and increased libido. It has been reported to induce reversible neurological impairment in multiple sclerosis patients, which led to the halt of an ongoing clinical trial. “ Though exceedingly rare, extrapyramidal side-effects (such as dystonic reactions, etc.) may occur, in particular, in the younger population”