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Anxiety Community
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Difference between SSRIs and Tricylics
by suzi-q, Jun 11, 2007 12:00AM
What is the difference between a tricyclic and an ssri? I see that many people are on them and have heard (from RCA) that they are superior to ssri's. Does anyone have any info on the difference between them???
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Tricyclic Antidepressants (TCA's for short), inhibit the re-uptake of norepinephrine, dopamine, and serotonin, and possess mild H1 receptor activity (anti-histimine). Like the SSRI's, there are different types of Tricyclics available, some are weaker (or more sedating) than others, and some target depression only, while some target depression and anxiety (or OCD). Side effects are largely due to their anticholinergic effect, and may include: Visual disturbance, tachycardia, constipation, urinary retention, and cardiac conduction abnormalities (rare).
Selective Serotonin Re-Uptake Inhibitors primarily inhibit the re-uptake of Serotonin only. The newer SNRI's (Selective Norepinephrine Re-Uptake Inhibitors) target both Serotonin and Norepinephrine.
SSRI's target 5-HT receptors, of which three types exsist: (A) 5-HT1, and (B) 5-HT2, and (C) 5-HT3
(A) Stimulation of 5-HT1 receptors is associated with antidepressant and anxiolytic effects
(B) Stimulation of 5-HT2 receptors is associated with nervousness, insomnia, and sexual dysfunction
(C) Stimulation of 5-HT3 receptors is associated with nausea and headache
*Most* SSRI's are not *selective* in which 5-HT receptor they target, which means most of them carry all of the nasty side effects listed in (B) and (C) above. This is the problem with SSRI's, and this is why they carry with them a constellation of adverse side effects. Some of the newer SNRI's supposedly are more specific in which 5HT receptor they target. Since most are not *selective*, trial and error is in order to find the proper one that may work for you.
While the side effect profile is lower for TCA's, they are more potent drugs (targeting three separate neurotransmitters), and they are more selective in their action. The downfall to using them over the SSRI's is the possibility of severe adverse cardiovascular effects (depending on the Tricyclic chosen), and the risk of death from overdose or attempted suicide. They are extremely toxic in overdose (unlike most SSRI's).
Common TCA's:
Imipramine (Tofranil®)
Desipramine (Norpramin®, Pertofrane®)
Trimipramine (Surmontil®)
Clomipramine (Anafranil®)
Amitriptyline (Elavil®, Endep®, Tryptanol®, Trepiline®)
Nortriptyline (Pamelor®)
Protriptyline (Vivactil®)
Doxepin (Adapin®, Sinequan®)
The most commonly used TCA's for anxiety are Sinequan, Elavil, Anafranil, and Pamelor. The others are best reserved for depression, as they are more stimulating. Of the types listed, Sinequan is the most mild, and the least likely to cause side effects. Sinequan was the first drug of its kind to be introduced as a combination antidepressant/anxiolytic, hitting the market in 1969.
Note for Suzi-Q: The Merck Manual states "Paroxetine (Paxil) causes withdrawal symptoms if discontinued abruptly"
Since Paxil actually works for you in combination with BuSpar, you'll probably want to remain on that combination unless it quits working.
TCA's and SSRI's/SNRI's should never be combined together.
-Ryan
Suzi