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dangerousdave

help me with some med math

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say it takes 6 weeks for lexapro to fully kick in

 

if i took it for 3 weeks, then switched to a different ssri, would the new ssri pick up where the other left off, or would it start over completely.

 

make sense?

 

 

 

 

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I believe that because it's a completely different med it would "start over."

Edited by jt07

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No it wouldn't be like starting over. All SSRI's have the same mechanism of action in inhibiting the reuptake of serotonin. Some just are more potent at it, some are more selective(in just messing with serotonin), different half lives, etc....but they all do basically do the same thing when it comes to serotonin.......they keep it from being uptaken and the result is you have more serotonin in the synapses. If you are taking one SSRI for a period of time, all that extra serotonin is not just going to suddenly dissappear just because you switched to a different SSRI. That doesnt mean that it would be a smooth transition. Some people do better on one SSRI than others(goes back to potency, selectivity, etc..), but it wouldnt be like starting over.

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Not when it comes to serotonin reputake inhibition. Id like you to explain to me how simply switching to another SSRI means it's essentially like he was never taking an SSRI at all before that switch.....

Maybe you all are talking about something else.

Edited by quiet storm

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Not when it comes to serotonin reputake inhibition. Id like you to explain to me how simply switching to another SSRI means it's essentially like he was never taking an SSRI at all before that switch.....

Maybe you all are talking about something else.

You may be correct theoretically. But in reality, it is starting over. I've done it. I know many others who have done it. I've had pdocs tell me that I need to give a med six weeks when I've switched. When you change meds, the clock starts over.

 

Edit: Since you are going against the generally accepted lore, do you have any research to back up your assertion that if you take one SSRI and then switch that the second one then will begin to work sooner than it ordinarily would when taken from scratch? Not trying to jump on you -- I really am interested.

Edited by jt07

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I have no idea, quiet storm, but I can theorize that drugs that do the same thing do them in a different way; so one drug might effect serotonin by path a and another through path b. The first drug isn't working on path a and has done nothing for path b. So when you start on the second drug, you are starting over again.

 

Maybe there's some overlap if path a is getting some benefit and the half life of the first drug keeps things going a little bit, but I'm guessing that's a minor effect.

 

And then there are the gremlins.

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I guess we'll just agree to disagree. Switching to another SSRI is not starting over when it comes to the serotonin that is floating around in your head. The extra serotonin in your brain is not going to go back to baseline levels just because you switched SSRI's. An SSRI is an SSRI is an SSRI......

If you're so sure of the answer why did you even ask the question?

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I have no idea, quiet storm, but I can theorize that drugs that do the same thing do them in a different way; so one drug might effect serotonin by path a and another through path b. The first drug isn't working on path a and has done nothing for path b. So when you start on the second drug, you are starting over again.

Maybe there's some overlap if path a is getting some benefit and the half life of the first drug keeps things going a little bit, but I'm guessing that's a minor effect.

And then there are the gremlins.

SSRI's all function the same. If they didn't it wouldn't be called an SSRI. YES, They all have some differences but when it comes to SEROTONIN REUPTAKE INHIBITION....THEY HAVE THE SAME MECHANISM OF ACTION. If they didn't they wouldn't be classified as an SSRI. Edited by quiet storm

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If you check the prescribing information sheet, you will see under "mechanism of action" that these meds are "thought to work" through serotonin reuptake inhibition. In other words, we don't know 100% exactly how they do work. Having taken many different classes of meds in my life, I've found that trying to figure out what will work based on neurotransmitters is a fool's errand. Among the SSRIs, only citalopram works for me. If they all are equal, why is it that only one works for me not the others?

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Not when it comes to serotonin reputake inhibition. Id like you to explain to me how simply switching to another SSRI means it's essentially like he was never taking an SSRI at all before that switch.....

Maybe you all are talking about something else.

You may be correct theoretically. But in reality, it is starting over. I've done it. I know many others who have done it. I've had pdocs tell me that I need to give a med six weeks when I've switched. When you change meds, the clock starts over.

 

Edit: Since you are going against the generally accepted lore, do you have any research to back up your assertion that if you take one SSRI and then switch that the second one then will begin to work sooner than it ordinarily would when taken from scratch? Not trying to jump on you -- I really am interested.

Naw. Show me research that says it can't happen sooner........I'm not saying anything definitively WILL/WILL NOT happen when it comes to the AD's efficacy. Everybody is different. But from a pharmacological...pharmakinetic.....whatever you call it standpoint, it is absolutely untrue that switching SSRI's is like starting over.

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If you check the prescribing information sheet, you will see under "mechanism of action" that these meds are "thought to work" through serotonin reuptake inhibition. In other words, we don't know 100% exactly how they do work. Having taken many different classes of meds in my life, I've found that trying to figure out what will work based on neurotransmitters is a fool's errand. Among the SSRIs, only citalopram works for me. If they all are equal, why is it that only one works for me not the others?

Did you just start this thread to argue? Like I said if you were so sure of the answer why ask the question. I'm out. Got better things to do with my Friday night.....

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If you check the prescribing information sheet, you will see under "mechanism of action" that these meds are "thought to work" through serotonin reuptake inhibition. In other words, we don't know 100% exactly how they do work. Having taken many different classes of meds in my life, I've found that trying to figure out what will work based on neurotransmitters is a fool's errand. Among the SSRIs, only citalopram works for me. If they all are equal, why is it that only one works for me not the others?

Did you just start this thread to argue? Like I said if you were so sure of the answer why ask the question. I'm out. Got better things to do with my Friday night.....

 

I didn't start this thread. I'm not the OP. Moreover, I'm not trying to argue but discuss.

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DangerousDave -- Outside of this "starting over debate," there's the likelihood that the pdoc is going to recommend you taper off the lexapro and get it out of your system before you start on the second drug. On top of that, you usually start on a lower dose and ramp up. It's unlikely you'd be advised to swing from one to another like a monkey in the canopy.

 

I'm amusing myself wondering what triggered this question. The scenario I favor on is that you realized you were depressed, had a friend who had three weeks worth of lexapro. You started taking the lexapro and are seeing a doctor in two weeks but are worried that you might get a prescription for a different SSRI.

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Changing meds won't necessarily make you go backwards but any benefit of the new drug over the old drug usually take a few weeks to show up.

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Now, I don't profess to being a scientist or have any medical expertise. So this might be really ham-fisted and if someone knows better, please add to this. Anyway, I'm going to quickly compare Lexapro and Zoloft:
 
Bioavaibility
Lexapro - 80%
Zoloft - 44%
 
Protein Binding
Lexapro - 56%
Zoloft - 98.5%

 

To me, the above are indicative of Lexapro and Zoloft being medication with different mechanisms. So while they may both achieve the same result - serotonin inhibition - they don't necessarily go about it in the same way. Therefore, it's logical to me that if you start one med and then move onto another, you would be starting over.

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jt07, I apologize. I feel kind of dumb now for accusing you of starting something. Guess I got a little carried away.

 

But anyway, yes all SSRI's DO  act differently in some ways. I mentioned as much earlier. I even talked about some of this in another post the other day. That zoloft is almost a mild dopamine reuptake inihbitor. Some are more potent at stopping serotonin reuptake. Some are a little less selective in that they hit on other things(but really not much compared to older TCA's, hence usually less side effects). They all have different half lives. Bioavailability. And yes people do not metabolize all drugs the same. Some are faster metabolizers, some are slower.....I totally agree that all this can make a difference.

 

BUT, the mechanism by which they inhibit the reuptake of serotonin IS THE SAME. They all act on the "serotonin transporter" effectively stopping it from reuptaking serotonin. In my argument, how fast, how slow....however in the heck it goes about doing it.....in the end it they all act on the serotonin transporter.

 

If more serotonin is the answer to your problems, and for some it is, some it isnt, then I stand by my argument that jumping from one to another may not necessarily mean starting over. The serotonin you gained from your first SSRI is not suddenly going to go back down to what it was before you were taking anything. 

 

Answer me why they give people prozac when they are having hellish withdrawals from something like effexor or cymbalta? Number one reason is half life. Prozac has a huge half life. Effexor and cymbalta dont. But you know what else makes the withdrawal so much easier? Because prozac is still picking up alot of the serotonin reuptake inhibition, but decreasing it much slower. 

 

All SSRI's, in the end, no matter how bioavailable, how fast it does it, how slow it does it, accomplishes giving you more serotonin in the same way. Thats why they are called SSRI's. They inhibit reuptake. You know why remeron isnt an SSRI? Because it doesnt do it the same way. It acts differently. It actually makes your brain produce more serotonin(and antagonizes other receptors) and norepinephrine. These are different classes of AD's. They are classified in the same categories for a reason.

Edited by quiet storm

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Out of curiosity, and I truly don't mean to argue, I'm just wondering ... what about benzos?  They are in a category, but I know from experience that they all don't work the same, and I need to wean off one before going onto another.  Take klonopin for example, I tried going from that (meaning stopping it and starting another benzo) to Xanax, and I had major withdrawal symptoms, where pdoc had me wean down on klonopin even while starting xanax.  And other benzos I've tried don't work the same for me.

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Benzos act on gaba receptors. Mainly Gaba-A receptors. GABA is one of the main inhibitory neurotransmitters in the human body. Benzos are agonists(they activate) on GABA receptors. To give a good example of another GABA agonist....think ethanol. That's why those few glasses of wine relax you and make you feel good. Activating gaba receptors relaxes you. Makes you sleep better. Takes away anxiety. Another reason they detox alcoholics who are going into withdrawal with benzos, The benzo replaces that really shitty vodka the were guzzling. We are all full of neurotransmitters, None of this is magic. Every single drug you put in you interacts with neurotransmitters you produce.

My guess is it all comes down to half life and potency. Xanax is super fast acting, hits hard, and then dies real quick. Hence why it's considered the most abusable. It's just a bunch of peaks and valleys. Which in the psych community the common reasoning is if you are going to be on something long term for anxiety, klonopin or something with a long half life is much preferable over Xanax. Basically with Xanax, you're just not that stable over the course of a day unless you hit taking it at just the right time. If I remember right the half life of klonopin is about 5 times longer than Xanax. It's smoooooother.

But it is a good example on another class of psychoactive drug that basically acts and functions one way(as far as mechanism of action..meaning it agonizes gaba receptors)across the whole class of drugs.Benzos are much more targeted in that manner compared to AD's.


Just my opinion.

Edited by quiet storm

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DangerousDave -- Outside of this "starting over debate," there's the likelihood that the pdoc is going to recommend you taper off the lexapro and get it out of your system before you start on the second drug. On top of that, you usually start on a lower dose and ramp up. It's unlikely you'd be advised to swing from one to another like a monkey in the canopy.

 

I'm amusing myself wondering what triggered this question. The scenario I favor on is that you realized you were depressed, had a friend who had three weeks worth of lexapro. You started taking the lexapro and are seeing a doctor in two weeks but are worried that you might get a prescription for a different SSRI.

looks like i started a shit storm.  its been very informative and entertaining thanks all.  and you ^ are almost spot on.  my father is a physician and he started me on lexapro for long term anxiety treatment.  the question came because i don't see my pdoc for another 3 weeks and i've been feeling some side affects that make me want to consider changing.  however i don't want to change if it "starts over" because i want to see how well having an ssri for anxiety really works.  "starting over" would prolong that.

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