# Lidocaine



## mikie (Sep 27, 2008)

Ok, this is probably going to sound like a silly question, but I'm going to ask anyways :blush:

The lidocaine used in ACLS, how does it differ from the  lidocaine used as a local anesthetic (for sutures, etc)?  I can't be the same, can it?

I'm sure the answer is difficult, pharmacology speaking...but something would be nice.

Thanks!


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## AlaskaEMT (Sep 27, 2008)

mikie333 said:


> can it?



Yes.  It can


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## mycrofft (Sep 27, 2008)

*Oh, yes. Indeed it can.*

OKOK.
Same chemical, different strengths are used for different purposes. Additives are used for appropriate uses, to alter the pH, or, in cases where you want it to last a long time, epi is added to constrict local vessels. This can have side effect by cutting off vital blood flow to a digit, concha of the ear, etc and cause necrosis. Used in dental work, the epi goes into your central circulation relatively rapidly and some folks can't take it, requiring the use of other local anesthetics such as carbocaine.

Viscous lidocaine is the same chemical as well but in a gel. Too much can be deadly:

http://en.wikipedia.org/wiki/Csilla_Molnár


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## mikie (Sep 28, 2008)

mycrofft said:


> Viscous lidocaine is the same chemical as well but in a gel. Too much can be deadly



Thanks for the explanation.  Interesting that you knew of that person (Wikipedia)


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## pumper12fireman (Sep 28, 2008)

That's why lidocaine is contraindicated in heart blocks. It "numbs" the ventricles, and in a situation where the impulse isn't getting down to the ventricles, numbing the ventricles is a bad, bad thing.


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## Ridryder911 (Sep 28, 2008)

pumper12fireman said:


> That's why lidocaine is contraindicated in heart blocks. It "numbs" the ventricles, and in a situation where the impulse isn't getting down to the ventricles, numbing the ventricles is a bad, bad thing.



*NO, NO , NO , NO, NO !!! *That is NOT why it is NOT used!!!

Who continues to teach such non-sense?


As well it is the same Lidocaine! Lidocaine comes in various forms. Lidocaine 1% and 2% and then there those with (Epi) called *with* (without -without EPi) for vasculature areas such as the scalp (which is contraindicated for use in dermal areas of the nose, penis, and toes) 

Sodium Bicarbonate can be added to reduce the stinging (the pH causing the pain). 

R/r 911


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## boingo (Sep 28, 2008)

Naples Fire test question:lol:


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## pumper12fireman (Sep 28, 2008)

Ridryder911 said:


> *NO, NO , NO , NO, NO !!! *That is NOT why it is NOT used!!!
> 
> Who continues to teach such non-sense?
> 
> ...



The guy that taught me that has helped contribute to a few different textbooks. So, I researched for a bit and wasn't able to come up with anything different, other than lidocaine used in heart blocks may worsen the heart block. The patho of "the numbing" effect is what was always taught to me, through different people as well. I'm curious, not arguing, why then, it's contraindicated?


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## VentMedic (Sep 28, 2008)

> It "numbs" the ventricles, and in a situation where the impulse isn't getting down to the ventricles, numbing the ventricles is a bad, bad thing.


Can you provide a reference to where you saw this in writing?


Does anything in the lecture linked below look familiar pertaining to Class 1B meds?

http://www.musc.edu/pharm/antiarrhyth2_3.pdf


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## pumper12fireman (Sep 28, 2008)

VentMedic said:


> Can you provide a reference to where you saw this in writing?
> 
> 
> Does anything in the lecture linked below look familiar pertaining to Class 1B meds?
> ...




No sir, I can't. I just specifically remember our arrhythmia instructor speaking of that. Saying, exactly that. It was something along the lines of "in a sick heart, trying to numb the ventricles can be a bad thing", in reference to amiodarone vs lidocaine discussion. 

And yes it does look familiar. I went back and reviewed a lecture very similar to that and I see now where that is definitely incorrect.


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## el Murpharino (Sep 28, 2008)

Lido alters the depolarization threshold of the heart muscle by blocking the sodium channels in the cell membranes...by blocking these channels, you won't have an action potential.  That's kind of dumbing it down, but hopefully it's accurate (I'm tired, and hope to not get too into this subject...or be wrong).


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## mycrofft (Sep 28, 2008)

*Lido can reduce ventricular irritability, but can impede*

conductive pathways by the same token. If your conductive pathways are already insulted*, making them even less capable is unhelpful. 
Roger, Ryder.



*Hey, Purkinje, your mama dress you like that?!".


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## Ridryder911 (Sep 29, 2008)

ding.....ding...ding.. we have a winner ! 

I cannot stand the description of "numbing" the heart as I have heard it repeated more than here. I don't care who, what they wrote, authored, etc.. then they should had known better. 

I had a newbie tell me that once ( I said once) after a writing a dissertation, he fully understood the difference....

R/r 911


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## Jon (Sep 29, 2008)

Ridryder911 said:


> ding.....ding...ding.. we have a winner !
> 
> I cannot stand the description of "numbing" the heart as I have heard it repeated more than here. I don't care who, what they wrote, authored, etc.. then they should had known better.
> 
> ...


C'mon... You have to numb Vance and Virgina Ventricle... so that Sidney Sinus can do his thing.

Sound about right, Rid?


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## mikie (Sep 29, 2008)

Jon said:


> C'mon... You have to numb Vance and Virgina Ventricle... so that Sidney Sinus can do his thing.



say what? :wacko:


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## VentMedic (Sep 29, 2008)

Jon said:


> C'mon... You have to numb Vance and Virgina Ventricle... so that Sidney Sinus can do his thing.


 
I was happy to see Dubin's book become a standard even with his past. Dr. Caroline made a great contribution to EMS education and in all fairness, she may have known some of her audience's lack of prerequisites and preparation.


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## Jon (Sep 29, 2008)

mikie333 said:


> say what? :wacko:


http://www.jbpub.com/catalog/9780763729073/


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## BruceD (Oct 4, 2008)

Ridryder911 said:


> ding.....ding...ding.. we have a winner !
> 
> I cannot stand the description of "numbing" the heart as I have heard it repeated more than here. I don't care who, what they wrote, authored, etc.. then they should had known better.
> 
> ...



OH come on Rid!  You know as well as I do that's why we use it!  It numbs the heart so we can't feel the pain of the MI we just had, that's why we push it!

Don't give me that stuff about Lidocaine blocking fast Na+ channels, that's all stuff made up by self-important physiologists and pharmacists.

ALSO there is NO literature supporting your position, I insist it's simply magic at work.


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## Sasha (Oct 4, 2008)

mycrofft said:


> conductive pathways by the same token. If your conductive pathways are already insulted*, making them even less capable is unhelpful.
> Roger, Ryder.
> 
> 
> ...



Youre so cute!!:lol:


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## rhan101277 (Feb 10, 2010)

I to have questions about this drug.  I know its a sodium channel blocker and it is used for to treat arrhythmias.  I realized that it slows conduction time therefore it may/should convert tachydysrhythmias.  

However my drug book specifically says that it increases electrical stimulation threshold, which made me think it took more electrical activity to overcome the drugs effects.  Which I believed was why the 1% solution was used to mitigate pain for certain procedures.

Know I also realize the 2% is used for cardiac.  Question is, when using this 1% how does slowing the pain signal help with pain, if it is going to get there anyhow?

Thanks


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## MrBrown (Feb 10, 2010)

While this may be somewhat simplistic; I was taught that it blocks sodium channels in the nerve fibres so that they are unable to transmit the pain "signal" if you will higher up into the nervous system and thus we do not feel them

I'd have to get my A&P book out and look at the nervous system to get all technical but I think the best analogy is like closing off the on-ramp to the freeway, you can't get on.

We still have SC 2% lidocaine (spelt lignocaine) for IV cannulation but I have never seen it used and it's 10x easier to just cannulate somebody rather than piss about with lido.

As for antiarrythmatic properties, well I can't say as that was before my time we use amiodarone and have done since 2005.


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## Melclin (Feb 11, 2010)

MrBrown said:


> We still have SC 2% lidocaine (spelt lignocaine) for IV cannulation but I have never seen it used and it's 10x easier to just cannulate somebody rather than piss about with lido.



For cannulation? Bunch of sheilas you lot.

We have it for combination with Ceftriaxone when going with the IM route in cases where u can't get an IV. So as you can imagine it pretty much just collects dust.


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## MrBrown (Feb 11, 2010)

Melclin said:


> For cannulation? Bunch of sheilas you lot.
> 
> We have it for combination with Ceftriaxone when going with the IM route in cases where u can't get an IV. So as you can imagine it pretty much just collects dust.



We have it, never seen it used.  The ONE time I have heard of somebody using it they said it was such a pain up the arse it was easier to ever use it again!

Can also use a little 2% lido to flush an IO prior to giving meds as apparently that hurts just a bit


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## rhan101277 (Feb 11, 2010)

MrBrown said:


> While this may be somewhat simplistic; I was taught that it blocks sodium channels in the nerve fibres so that they are unable to transmit the pain "signal" if you will higher up into the nervous system and thus we do not feel them
> 
> I'd have to get my A&P book out and look at the nervous system to get all technical but I think the best analogy is like closing off the on-ramp to the freeway, you can't get on.
> 
> ...



It doesn't block them totally, some still get through and thus it takes longer as the signal moves.  Maybe the brain receives the signal and disregards it due to the time delay or some such.


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## fma08 (Feb 11, 2010)

rhan101277 said:


> I to have questions about this drug.  I know its a sodium channel blocker and it is used for to treat arrhythmias.  I realized that it slows conduction time therefore it may/should convert tachydysrhythmias.
> 
> However my drug book specifically says that it increases electrical stimulation threshold, which made me think it took more electrical activity to overcome the drugs effects.  Which I believed was why the 1% solution was used to mitigate pain for certain procedures.
> 
> ...



It increases the threshold to above normal levels. So the "pain" will send normal levels of electrical excitement, but since those levels that were able to create an action potential before, they are no longer able to do so. So if the lidocaine is working properly, there shouldn't be signals going. It slows the action of the sodium channels (1), not the signal.

1: http://emedicine.medscape.com/article/167309-overview


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