Posted by Lorraine on February 2, 2002, at 16:30:21
In reply to Re: anticonvulsants for anxiety » 3 Beer Effect, posted by Elizabeth on February 2, 2002, at 14:24:28
Elizabeth: This link is to an interesting slide re vigabatrin and its effects in the brain. Below is a summary of a rat study re its mode of action. I hope this is helpful. I'll let you know what the cdoc says after I see him and thanks for your other thoughts re my pulse etc. It will be useful when I meet with my pdoc on Tuesday (after my cdoc on Monday.)
Lorraine
U K U N E U R O S C I E N C E P U B L I C A T I O N S Halonen T, Pitkänen A, Riekkinen PJ.Administration of vigabatrin (gamma-vinyl-gamma-aminobutyric acid) affects the levels of both inhibitory and excitatory amino acids in rat cerebrospinal fluid.J Neurochem 1990;55:1870-1874AbstractThe effect of vigabatrin (gamma-vinyl-gamma-aminobutyric acid), a new anticonvulsant drug, on the transmitter amino acids in rat cisternal CSF was studied. CSF was collected through a permanently implanted polyethylene cannula from freely moving rats at 5, 24, 48, and 96 h after administration of 1,000 mg/kg of vigabatrin. The free gamma-aminobutyric acid (GABA) level was elevated maximally (13.5-fold; p less than 0.01) at 24 h after injection. The homocarnosine (GABA-histidine) level also was increased (123%; p less than 0.01) at 24 h after injection, and its concentration remained at the same level for the next 3 days. Glycine and taurine concentrations had increased [31% (p less than 0.05) and 63% (p less than 0.01), respectively] at 5 h after injection. It is interesting that the levels of glutamate and aspartate increased [330% (p less than 0.05) and 421% (p less than 0.01), respectively] at 96 h after injection, the time when the free GABA level had returned to the baseline concentration and the vigabatrin level was 3% of the maximal concentration. The present study indicates that a single dose of vigabatrin in rats elevates levels of both the inhibitory and excitatory amino acids in CSF. However, the temporal profile of observed changes in relation to vigabatrin injection shows that neither the long-lasting elevation of GABA content nor the increase in glutamate and aspartate levels correlates with the level of vigabatrin in CSF. These findings suggest that the excitatory mechanisms are also augmented following acute administration of vigabatrin, especially when the content of GABA had decreased to the baseline level and the level of vigabatrin was low.
Hope this helps.Lorraine
> > I was recently taking Neurontin 900 mg/day but it hasn't done anything for my social phobia, only seems to make it worse.
>
> Is it really making your SP worse, or is it just making you so tired that you don't have the energy to go out? My idea would be to decrease the dose to something more tolerable, then increase it again *gradually* as needed.
>
> > Does Gabitril (tiagabine) function as a mood-stabilizer or an anxiolytic/anti-anxiety drug?
>
> I've been wondering that myself, but I haven't gotten any answers. I'm interested in Sabril (vigabatrin) too; it's been looked at a bit for panic disorder as well as in some animal models of anxiety.
>
> > On paper, it looks like it would help with Social Phobia since it potentiates GABA like alcohol (which I still think is the best social phobia/anxiolytic drug ever), which the benzos also do but through a different mechanism.
>
> Gabitril is a GABA reuptake inhibitor. I don't think that it potentiates GABA, but rather increases the amount available.
>
> Anyway, here's a citation for an article that might address the issue:
>
> Ketter TA, Post RM, Theodore WH.
> Positive and negative psychiatric effects of antiepileptic drugs in patients with seizure disorders.
> Neurology 1999; 53(5 Suppl 2): S53-67.
>
> (The abstract didn't go into much detail.)
>
> -elizabeth
poster:Lorraine
thread:92589
URL: http://www.dr-bob.org/babble/20020131/msgs/92640.html