# amitriptyline overdose (drug interventions)



## coolidge (Dec 24, 2008)

What algorithm do you follow for an amitriptyline overdose?


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## Ridryder911 (Dec 24, 2008)

Here is a link to DFW in service on TCA overdose and their protocols, (which is similar to what I use). 

http://www.utsw.ws/guestquizindex.htm

Look at the TCA link, and it is narrated by a physician, with power point. 

R/r 9011


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## coolidge (Dec 24, 2008)

Thank you very much.


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## bonedog (Dec 25, 2008)

ALKALIZE, QRS wider than 10, widening QT, alkalize.....


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## Bosco578 (Dec 25, 2008)

*Life sucks*

Just let them die. Life sucks. No matter how hard one tries. Life sucks.


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## mycrofft (Dec 25, 2008)

*Bosco578, Merry Christmas!!*

You get your butt kicked by an Elavil overdoser, too?


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## eric2068 (Jan 4, 2009)

*TCA od*

Bicarb baby, Bicarb.


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## sdadam (Jan 6, 2009)

Why bicarb?


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## Ridryder911 (Jan 6, 2009)

sdadam said:


> Why bicarb?



Watch the attached link for a good inservice from DFW EMS and the physician will give you the in and outs. 

R/r 911


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## eric2068 (Jan 7, 2009)

To combat the acidosis. Cool stuff.


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## maxwell (Jan 31, 2009)

Bosco578 said:


> Just let them die. Life sucks. No matter how hard one tries. Life sucks.



Completely inappropriate.  Let them die?  Really?

NaHCO_3 is the answer.  Lots of bicarb.  It's not completely an acidosis thing.  For all intents and purposes, it's a QRS thing.


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## emtbill (Feb 1, 2009)

Well since this post has just been necro'd...anyone have a downloaded copy of the TCA lecture link Rid posted earlier that they can host elsewhere? The link on the site is dead.


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## coolidge (Jul 29, 2010)

*amitriptyline OD*

Did anyone discover the new web site for tricyclic OD tx?
Thanks


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## MediMike (Jul 29, 2010)

The administration of Sod Bicarb alkalinizes the blood, resulting in an increased binding of the TCA's, therefore (sounds pretentious, sorry ) a decreased bioavailability of the drug


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## 18G (Jul 29, 2010)

Sodium bicarb as MediMike has said increases the alkalinity of the blood which increases protein binding of the TCA molecules making them unable to exert their effect. A drug that is protein bound is not able to exert its effect. The drug has to be free.

The sodium bicarb also increases elimination of the drug through urination.


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## Fox800 (Jul 30, 2010)

MediMike said:


> The administration of Sod Bicarb alkalinizes the blood, resulting in an increased binding of the TCA's, therefore (sounds pretentious, sorry ) a decreased bioavailability of the drug



Bingo. It's not about acidosis.


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## mycrofft (Jul 30, 2010)

*Good. Without it they rev and spin and then*

............collapse.


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## sir.shocksalot (Jul 31, 2010)

18G said:


> Sodium bicarb as MediMike has said increases the alkalinity of the blood which increases protein binding of the TCA molecules making them unable to exert their effect. A drug that is protein bound is not able to exert its effect. The drug has to be free.
> 
> The sodium bicarb also increases elimination of the drug through urination.


I never knew this, very informative 
So TCA can only be active at a neutral/normal pH's? What causes the QRS widening? Is it a potassium deal?


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## 18G (Jul 31, 2010)

It's my understanding that the QRS widening seen in TCA OD comes from the sodium channel blockade effect. 


From eMedicine:
"Serum alkalinization to a pH of 7.45-7.55 appears to uncouple tricyclic antidepressant (TCA) from myocardial sodium channels, and the sodium load increases extracellular sodium concentration, improving the gradient across the channel."


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## Jay (Aug 1, 2010)

OK, folks, I would say bicarb is a good choice if treating based on the ECG findings, however since Amitriptyline is an older tricyclic antidepressant/SNRI giving a dose of activated charcoal would be most beneficial if the OD was acute and you have supporting evidance that the dose would be given within one hour of the oral intake. 

Since we are talking SNRI, we would have similar issues when comparing this to a Tramadol overdose, one reason why Elavil and Tramadol are contraindicated. Both (especially together but independently) will cause Serotonin Syndrome where each "piece" can be individually managed, e.g. benzos, airway management, epinephrine (to raise the pulse/BP to be WNL), etc.

Remember that in all of the above cases Serotonin Syndrome should resolve in <24 hours. The key is management of the symptoms if the initial interference such as activated charcoal and bicarb (if the ECG supports it) do not resolve it, once the drugs have tapered down in the system there may be some after-effects but generally things will look positive. 

The only exception to the Serotonin Syndrome with an Amitriptyline OD and that of Tramadol is that Tramadol additionally acts on the μ-opioid receptor as well as causing the burst in serotonin. This in some cases can lead to a more intense withdrawal than that of other synthetic opioids (whether scheduled of not) and is *probably* why naloxone is not as effective at treating such an OD.


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## dmiracco (Aug 2, 2010)

The Bicarb is mainly given because of the Sodium in the medication because as the post earlier its the sodium channels being blocked prolongs the QRS interval it also secondarily helps with the acidosis. 
So after giving it the channels are flushed and reopen allowing the sodium the go in and out of the cell narrowing the QRS.


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## AnthonyTheEmt (Aug 3, 2010)

sdadam said:


> Why bicarb?



Bicarb is alkalotic and TCA's are acidotic


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## sdadam (Aug 3, 2010)

AnthonyTheEmt said:


> Bicarb is alkalotic and TCA's are acidotic



This is not the case.

I asked this question a long time ago because I wanted to stimulate conversation as it seemed people had a misunderstanding of the mechanisms through which Bicarb treats TCA toxicity.

It has been explained elsewhere in the thread to my satisfaction. (see the answers concerning NA channels and plasma protein binding)


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## Jay (Aug 5, 2010)

AnthonyTheEmt said:


> Bicarb is alkalotic and TCA's are acidotic


When comparing the pH levels from a chemical standpoint alone this may have some validity however the purpose of pushing bicarb for a TCA OD would be to specifically treat the wide QRS complex if it is seen on the ECG. I am seeing a lot of tangents on this post but if we get back to the basics, H's & T's from ACLS we will realize two very basic things when looking at this symptomatically: 

First, a hallmark of Hyperkalemia is the widening of the QRS complex which is the same symptom in our case of the TCA OD here, either way bicarb is used to treat.

Second, Acidosis or (Hydrogen Ion from our mnemonic) can be reversed with bicarb. In our case we are not so concerned about the acidosis because a TCA OD will cause the wide-QRS which should be reversed by bicarb. Absorbtion secondary to protein binding or the nature of the pH animal is something else altogether. 

Next, what about as I mentioned earlier, if acute and the patient is not overly symptomatic (yet) the administration of activated charcoal will work as part of the treatment plan, the caveat is a one hour time limit I believe, also I know as a fact it wont work if the OD occurred over a "long" duration since absorption has already set in. 

Finally, we see and hear all the time to treat the patient, not the numbers. So the real question, in my humble opinion would be to see what the symptoms are and to treat them because as I mentioned earlier the patient should be in the clear within 24 hours and can be downgraded from the ICU after 12 hours (strictly speaking in terms of Serotonin Syndrome) so as long as the patient is maintained properly the drug will work its way out of the body, the key is management of the overall patient to see them through that first day. Bottom line there is not much to do other than treat the symptoms in the pre-hospital setting.

One interesting segue about serotonin syndrome is that if the BP falls too low you will need a direct acting drug such as epinephrine to bring it back up, I do not believe that dopamine or dobutamine will work in this case. Someone please chime in if I am wrong about this.

I hope this does not sound too pretentious of me but its bugging me that so many people were wanting to slam bicarb... I feel getting back to the basics answers most questions including this one.


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## MrBrown (Aug 5, 2010)

Although the thought of Firefighters with 36 weeks of Paramedic education (and I use the term loosely) running around the DFW Metroplex scares the crap out of me, I must say Paul Pepe and the BioTel folks do great CE modules.

The new TCA module can be found here

http://www.utsw.ws/utsw/Lectures/TricyclicAntidepressantOverdose2007/player.html

Hello? Parkland? Yes, it's Dr Brown speaking, I work with the helicopter emergency medical services .... hmm yes I agree, I can't think of anywhere we might be able to land at the moment, hmmm, hang on, hey Oz, call the Dallas Police, see if they can shut down the Stemmons Freeway for a minute....


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## MrBrown (Aug 5, 2010)

Just missed edit time, bugger ... for TCA overdoses we infuse large doses of sodium ions which is basically two litres of fluid with blood pressure cuff wrapped around the bags


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