Posted by JohnX on October 7, 2001, at 6:57:18
In reply to Memantine soon to be approved? - AndrewB, posted by SLS on September 13, 2001, at 16:17:18
> It looks like memantine will soon be approved.
>
> Memantine is a drug being developed for the treatment of Alzheimer's Dementia. Of course, this doesn't exclude the possibility that it might be effective for treating other conditions. AndrewB, one of our many bright contributors of which I am not one, indicated not so long ago that memantine might have a place in treating certain psychiatric conditions. For now, I would rather defer to him or someone else to describe in more detail the therapeutic potential of this drug.
>
> Among the pharmacological properties that memantine might possess is the ability to block the NMDA receptor. This is really a subtype of the receptors known to be stimulated by the neurotransmitter glutamate, and are thus labelled glutamatergic. Glutamate-activated neurons are the most numerous of the excitatory type in the brain. It is thought that it is through an increase in glutamatergic neurotransmission that modafinil (Provigil) and adrafinil (Olmifon) produce their activating effects to promote wakefulness. This is in contrast to GABA-activated neurons (gamma-amino butyric acid), which act to inhibit or "calm-down" the excitatory neurons. For reasons that I do not yet understand, it seems that memantine can prevent the development of tolerance to certain drugs, including opioids and stimulants. A couple of people here reported that it allowed them to maintain a continuous response to the psychostimulants that helped to improve their mood. Adderal and Cylert were the drugs to which memantine was added. Previously, these people needed to cycle on and off these psychostimulants because the beneficial effects would disappear within three or four days.
>
> I hope Andrew is tuned-in so that he can offer some of his wisdom. In particular, I would like his feedback regarding the possibility that a partial antidepressant response to Lamictal might be an indicator of a more robust response to memantine. Perhaps memantine can prevent or reverse the emergence of SSRI "poop-out", or act as an adjunct whenever someone displays a pattern of responding to a particular antidepressant for only three days (me - TCAs and MAOIs).
>
> Anyway, I'd like to see what other people can come up with regarding memantine. It might be a good tool to treat depression and prevent neuronal degeneration.
>
>
> - ScottScott,
I've been following this medication closely.
I don't know of any medication in this class
that is currently in widespread use. The only
one I have come across in research is DXM
(dextromethorphan), the anti-tussive in OTCs
like robutussin DM. If you do a medline search
on dxm you will find that it, like mk-801, and
memantine pretty much all share this same property
of relieving sensitization in the VTA area of the
brain, thought to be the central point in
addiction.I actually found an interesting patent from
a neurologist that prescribes dxm with meds
that inhibit the liver enzyme cyp2d6. DXM
has a short 1/2 life and inhibiting the enzyme
gives it more legs. It sounds dangerous to me,
but the neurologists claims to have successfully
used this to treat addiction withdrawl,etc.Drugs that antagonize NMDA receptors (ketamine,
mk-801,dxm) have the potential to cause
psychotropic side effects and can actually paradoxically
induce neuronal damage in areas of the brain
where glutamate stimulates gaba!.Memantine is a non-competitive antagonist at
the NMDA receptor. It steps up to bat
if it sees a glutamate overflow. It appears to
not have as much potential for overkill like
the other antagonists.Forrest Labs is doing the clinical trials in
the US. A small biotech company called NTI
(neurobiological technologies) helped to introduce
the trials by coordinating the global pharmaceutical
manufacturers with the German company Merz, which
owns the patent.Anyways, in the US the FDA approvals will like
be initially for alzheimers and peripheral
neuropathy. However, some people believe the
med has many uses (as in addiction,tardive
dyskenisia, anti-spasmodic), etc. It will be
interesting to see if it is approved how many
"off-label" prescriptions will be written in
these other areas. 80% of Provigil's prescriptions
are "off-label" i.e. not for Narcolepsy.It would be interesting if Memantine was
proven effective at blocking tolerance to
stimulants and also being neuroprotective.
What would this mean to the psychiatric industry?
Will the shrinks be more likely to prescribe
stimulants for depression? They certainly work
faster than anti-depressants.Let's stay tuned.
-john
poster:JohnX
thread:78734
URL: http://www.dr-bob.org/babble/20011007/msgs/80514.html