Re: Norepinephrines role in panic and anxiety disorders
Originally Posted by
SideFX
Can anyone explain to me why the use of Norepinephrine blocking medications can have a positive effect on anxiety disorders. Ie. SNRI's and TCA's I can't understand how these types of medication can lower anxiety levels, in particular imipramine and clomiprimine, along with venlafaxine and other SNRI's ???
Antidepressants don't directly lower anxiety levels (or depression), but work by stimulating the growth of neurons in the hippocampal regions of the brain. The new cells and the connections they forge create the therapeutic response, not the meds per se. How the ADs do this is complicated and still poorly understood, but lowering the synthesis and expression of serotonin and/or noradrenaline aka norepinephrine (NA) - and probably also dopamine in the case of MAOI class ADs, although, afaik, there in no research demonstrating this - seems to be a vital part of the process. Noradrenaline reuptake inhibitors (NRIs) like desipramine, nortriptyline, lofepramine and reboxetine can be just as effective as SSRIs. Hitting both serotonin and noradrenaline pathways seems to be more potent than targeting just one of the neurotransmitters and also lowers the risk of the med pooping-out.
Clomipramine (Anafranil) is the second most potent serotonin reuptake inhibitor (SRI) after paroxetine (Paxil) whereas imipramine (Tofranil) inhibits serotonin less, but it a more potent NRI. Amitriptyline is an even weaker SRI, but the most potent NRI of the serotonergic TCAs.
BTW - venlafaxine is not a true SNRI. Its designation is mostly about marketing, not chemistry. It only begins to inhibit NA reuptake at doses around 200mg and then still only modestly. Fluoxetine (Prozac), paroxetine (Paxil) and sertraline (Zoloft) are much more potent NRIs, albeit still only weak ones. Vortioxetine also inhibits NA to some extent being second only to paroxetine among the SSRIs.
Can someone kindly advise if switching from vorteoxatine to one of the above could be beneficial please. I really need to understand the rationale.
It is impossible to say whether you'd do better on a SNRI like duloxetine (Cymbalta), or one of the TCAs. Unfortunately, the only way to know is to try them.
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The opinions expressed above are based on my observations and, where applicable, interpretation of cited data and are general in nature. Consult your physician before acting on anything stated.