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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 5 of 5. This is the beginning of the thread.
Posted by JohnX2 on April 17, 2002, at 1:43:53
I'm interested in Lamictal's potential serotonergic properties, anyone know about this?I dug up this abstract indicating the medicine down regulates 5ht-1a receptors. Is the medicine some kinda SRI? I notice the medicine at a high dose gives me SRI like effects (mainly it feels a lot like Zoloft..bad things happen my emotions go flat and I get tension headaches and jaw pain) ....
1: Neurochem Int 2002 Apr;40(4):315-9 Related Articles, Books, LinkOut
Lamotrigine induced selective changes in 5-HT(1A) receptor mediated response in rat brain.Vinod KY, Subhash MN.
Department of Neurochemistry, National Institute of Mental Health and Neurosciences, P.B. No. 2900, Bangalore-560029, India.
A new anticonvulsant drug lamotrigine (LTG) has recently been reported to be effective in treating patients with bipolar affective disorder, depression and schizoaffective disorder, suggesting that it is a mood stabilizer. However, the mechanism of action underlying its efficacy in mood disorders is not understood. This study examined the in vivo effect of LTG on 5-HT(1A) receptor-mediated adenylyl cyclase (AC) response in regions of rat brain, as this pathway has been implicated in the therapeutic action of various classes of mood stabilizers. The density of 5-HT(1A) receptors was measured by radioligand binding assay using [(3)H]8-OH-DPAT (0.05-0.8nM) in frontal cortex and hippocampus of rats treated orally with LTG (5mg/kg) for 7 days. AC activity was assayed using [(3)H]ATP. The oral administration of LTG significantly decreased the density of cortical (50%, P<0.001) but not hippocampal 5-HT(1A) receptors, without significant change in the affinity of [(3)H]8-OH-DPAT to 5-HT(1A) receptor in these regions. There was no significant alteration in basal or forskolin-stimulated AC activity in either of regions. However, a significant decrease (P<0.01) in the inhibition of forskolin-stimulated AC activity by 8-OH-DPAT was observed only in cortical membranes of LTG treated rats when compared to control. These results suggest that one mode of action of LTG may be by the downregulation of cortical 5-HT(1A) receptor-mediated AC response.
PMID: 11792461 [PubMed - indexed for MEDLINE]
Posted by JohnX2 on April 17, 2002, at 1:47:50
In reply to Lamictal Serotonin Properties???????, posted by JohnX2 on April 17, 2002, at 1:43:53
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9809864&dopt=Abstract1: Eur J Pharmacol 1998 Sep 25;358(1):19-24 Related Articles, Books, LinkOut
Lamotrigine inhibits monoamine uptake in vitro and modulates 5-hydroxytryptamine uptake in rats.Southam E, Kirkby D, Higgins GA, Hagan RM.
Neuroscience Unit, Glaxo Wellcome Medicines Research Centre, Stevenage, Herts, UK. es36365@ggr.co.uk
Lamotrigine is a novel anticonvulsant drug which also stabilises mood in bipolar illness via an unknown mechanism. We report the concentration-dependent inhibition of 5-hydroxytryptamine (5-HT) uptake in both human platelets and rat brain synaptosomes (IC50s were 240 and 474 microM, respectively) by lamotrigine. Synaptosomal uptake of noradrenaline (IC50 239 microM) and dopamine (IC50 322 microM) was also inhibited. Tetrodotoxin failed to modulate 5-HT uptake suggesting that sodium channel blockade does not mediate the lamotrigine effect. Lithium, sodium valproate, zonisamide, and carbamazepine all possess anti-manic activity but only the latter inhibited 5-HT uptake. The inhibition of the p-chloroamphetamine-induced 5-HT syndrome in rats suggests that lamotrigine also inhibits 5-HT uptake in vivo. These effects probably reflect an affinity for biogenic amine transporters. However, at present, it remains uncertain whether, at clinically effective doses, these effects contribute significantly to the efficacy of lamotrigine in bipolar illness.
PMID: 9809864 [PubMed - indexed for MEDLINE]
Posted by JohnX2 on April 17, 2002, at 1:52:28
In reply to Lamictal Serotonin Properties???????, posted by JohnX2 on April 17, 2002, at 1:43:53
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9778610&dopt=Abstract1: Neuropsychobiology 1998 Oct;38(3):200-1 Related Articles, Books, LinkOut
Female genital disorder as adverse symptom of lamotrigine treatment. A serotoninergic effect?Erfurth A, Amann B, Grunze H.
Department of Psychiatry, University of Munich, Germany. erfurth@uni-muenster.de
The new anticonvulsant, lamotrigine, is becoming an important tool in the treatment of bipolar disorder, including bipolar depression. Its efficacy in bipolar depression might be linked to its inhibition of serotonin uptake. We present the case of a female schizoaffective patient successfully treated with 400 mg of lamotrigine developing considerable genital disorder, a side effect well known from the treatment with selective serotonin reuptake inhibitors (SSRIs). We suggest that female genital disorder induced by high doses of lamotrigine is a serotoninergic side effect.
PMID: 9778610 [PubMed - indexed for MEDLINE]
Posted by Morgana on April 18, 2002, at 23:31:51
In reply to Lamictal Serotonin Properties???????, posted by JohnX2 on April 17, 2002, at 1:43:53
John,
I am very sensitive to all SSRI's. I get all the lovely side effects, the sexual dysfunction one being the worst, but I haven't noticed any seratonin side effects with Lamictal. I take 200-mg 2x day. I'm not sure if that is considered a high dose or not. High for some I'm sure, not enough for others. My fiancé has increased his Lamictal to 300-mg 2x day, and is sensitive to seratonin as well, with no noticeable side effects.
Something new I've learned about Lamictal is that it does not provide a good cap for mania, but is highly effective for rapid cycling. Stanford has come out with new studies re the effectiveness of Lamictal and mania. Very interesting. The woman who runs the group I attend keeps encouraging me to have a good mania capper on hand. I've recently started Verapamil though, and have read that it has been used as a mood stabilizer with some success. Maybe the combination will provide a better 'safety net'.
Hope you're able to find the right cocktail. I know you have been struggling, especially with the Topomax.
Morgana, BPII – Nardil, Lamictal & Verapamil
P.S. I wanted to add that for me, an increase in seratonin seems to help with my headaches and migraines. Not sure how that works exactly, but I'm looking forward to the Nardil kicking in - in about 2-3 weeks. Neurologist says I have to wait a full 6 weeks to notice any benefit when it comes to the migraines.I'll keep my ear to the ground about recent studies on Lamictal. I have a friend who goes to Stanford and she always has the latest news.
Posted by seline on July 18, 2008, at 17:56:02
In reply to Lamictal Serotonin Properties???????, posted by JohnX2 on April 17, 2002, at 1:43:53
> I dug up this abstract indicating the medicine down regulates 5ht-1a receptors. Is the medicine some kinda SRI?
i think that if serotonin receptors are decreased, serotonin action is decreased. when serotonin shoots out of the presynapse and onto the postsynapse where the receptors are, that is when the activity happens; when less binding occurs cuz there are less holes to bind to, there's less action. so, lamictal would theoretically inhibit serotonin activity.
This is the end of the thread.
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