# epi and nitro



## jjoshh (Mar 22, 2012)

Could there be a pt prescribed epi and nitro?

 Say you come on a pt with anaphylactic shock and has a history of heart problems prescribed nitro, could he have chest pain with an anaphylactic reaction? and would you help adminsitor epi with a pt with heart probems and prescribed nitro? would .3mg of epi cause so much vasoconstriction that it would cause a heart attack? my book says no contraindications for administering epi.


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## Aidey (Mar 22, 2012)

What is one of the contraindications for giving nitro? What is one of the symptoms of anaphylaxis?


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## jjoshh (Mar 22, 2012)

below 90 systolic bp for nitro and low bp for anaphylactic


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## jjoshh (Mar 22, 2012)

my understanding then is it would not put much workload on the heart and would not create any chest pain if in anaphylactic shock


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## jjoshh (Mar 22, 2012)

what bp readings would you find with someone in severe anaphylactic shock?


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## bigbaldguy (Mar 22, 2012)

If they were experiencing severe anaphylaxis I would think the lesser of two evils would be to administer the epi, then deal with the possible side effects. If their anaphylaxis symptoms were mild I might hold off until they became more severe. On the other hand waiting might be a bad idea because if it progresses to far then you might have to administer more epi to get back in front of it. Also the dose of epi in an injector is fairly low. I wouldn't think it would make a huge difference in a person with heart issues.


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## jjoshh (Mar 22, 2012)

epi would cause vasoconstriction, increased heart rate and chest pain, could it cause a heart to go into V-Fib?


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## jjoshh (Mar 22, 2012)

thanks for the reply's


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## systemet (Mar 23, 2012)

jjoshh said:


> Could there be a pt prescribed epi and nitro?



Yes.  For example, someone with a history of an anaphylactic reaction who also has angina.



> Say you come on a pt with anaphylactic shock and has a history of heart problems prescribed nitro, could he have chest pain with an anaphylactic reaction?



Sure.  He/she could be hypotensive, resulting in a decreased oxygen supply to the myocardium, and anginal pain, or outright infarction.



> and would you help adminsitor epi with a pt with heart probems and prescribed nitro?



As a paramedic, yes, but I would tend to the lower side of the dosing, probably 0.3mg versus 0.5mg.  I would be even more hesitant than normal to give epinephrine IV.

This is a situation where the risk of causing an MI or an arrhythmia, or some other complication, with the epinephrine needs to be balanced against the danger of an untreated anaphylactic reaction.



> would .3mg of epi cause so much vasoconstriction that it would cause a heart attack?



Yes, it can.  It could also cause an arrhythmia, or a CVA, or any number of other complications.  And this is not just a risk in patients with prior diagnosed cardiac disease.  But the risk is probably greater in these individuals than in the general population of patients without prior diagnosed cardiac disease.

Of course, all that matters is the risk in the individual patient you're treating, which may be difficult to determine beforehand, and the outcome of your care, which you can only find out afterwards.



> my book says no contraindications for administering epi.



Well, that's your book giving an easy and simple answer to a potentially difficult and complicated question.  

It is probably safe to say that in most life-threatening presentations of anaphylaxis giving the epinephrine is better than withholding in, even in the presence of significant prior cardiac disease.


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## systemet (Mar 23, 2012)

jjoshh said:


> epi would cause vasoconstriction, increased heart rate and chest pain, could it cause a heart to go into V-Fib?



Yes.  Or pretty much any other perfusing or non-perfusing arrhythmia.  It's not benign.


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## mycrofft (Mar 23, 2012)

As "a fibber" (atrial fibrillation, pun intended), let me tell you, even the epi in dental injected lidocaine causes sensations of a tight chest and dyspnea. (NO, not allergic to lidocaine). I can imagine what an anaphylaxis dose would do. BUT, I might survive the former/epinephrine side effects, while the latter/anaphylaxis ...not so much.

If you came across an anaphylactoid pt with a medic alert bracelet for atrial fib or that says "NO EPI", what would your alternatives be, generally speaking? Maybe go with IV benadryl first? Or give the epi then try to modulate the side effects with a beta blocker? (Not the best way to use medicine, like log rolling using the pt as a log).


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## systemet (Mar 23, 2012)

mycrofft said:


> If you came across an anaphylactoid pt with a medic alert bracelet for atrial fib or that says "NO EPI", what would your alternatives be, generally speaking? Maybe go with IV benadryl first? Or give the epi then try to modulate the side effects with a beta blocker? (Not the best way to use medicine, like log rolling using the pt as a log).



I think this depends on the severity of the symptoms.  In most cases you're going to give the epinephrine with the same concern/caution that you would have giving it to someone with a concerning history for prior ischemic heart disease.  

If the symptoms are very mild, or the presentation is borderline for anaphylaxis, it might be tempting to give IV benadryl and then gauge the clinical response -- but you would want to be careful not to get caught out by a rapid deterioration.

If I gave epinephrine to someone with a history of AF mand got a rapid ventricular response, I think the treatment would depend on how rapid and how symptomatic the patient was.  I'd be reluctant to treat it with further medical therapy as you risk getting into a situation where "I gave C to treat B, that I created as a forseeable side effect of treating A, and now I have to deal with problem D".  

Unless the AF symptoms are severe, I'd probably just wait out the half-life of the epinephrine.  I would be reluctant to give beta-blockers in particular, for the same reason we don't use them in other sympathomimetic overdoses, unopposed alpha-stimulation of coronary vasoconstriction.

More serious issues occur when you have someone presenting with a critical arrhythmia, and severe anaphylaxis.  If you have someone in perfusing VT with no pressure, severe hypoxia, and lots of angioedema, the decision becomes more complicated.


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## Christopher (Mar 23, 2012)

Even if you're a patient with CAD and atrial fibrillation and _insert cardiac Hx here_, when you're having an anaphylactoid reaction your body should compensate for the decreased vascular resistance. I wouldn't be surprised if your AF patients would have a "rapid ventricular rate". A concern could be B-blockade due to normal medications interfering with any epinephrine administered.

As an EMT-Intermediate or Paramedic, one could consider Glucagon as an alternative chronotropic and inotropic agent, however, it will not improve the systemic vascular dilation quite like epinephrine would.

As an EMT-Basic, if your patient is having a true anaphylactic reaction there will not be a contraindication to the administration of Epinephrine. Unopposed distributive shock is your immediate concern. That being said, don't just hit them with an EpiPen because they have one and say they're allergic


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## mycrofft (Mar 23, 2012)

Glucagon: what about glycemic effects?
Regular meds: yeah, they can get complicated. Atrial fib pts can be getting such meds as anticoagulants, digoxin, beta blockers,  We chronic cardiacs need to carry a current list of meds and medic-alert device at all times.


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## NYMedic828 (Mar 23, 2012)

Clinical judgement, Clinical judgement, Clinical judgement...

Assess your patient...

Its pretty rare to find a member of the younger population prescribed nitro. So assuming the patient is older to begin with, epi is already considered a dangerous drug. The possibility of arrhythmia/chest pain are pretty real.

I am sure someone with far more pharmacological knowledge will step in, but I really don't see 0.3mg of epi causing enough coronary constriction to case an MI. 

For patients in arrest, we often gives 5mg IV. Thats over 15x the amount we give IM/SQ to a living patient. I know that 5mg of epi definitely isn't good for a patients body if they do survive, but 0.3mg is nothing by comparison.

If an elderly patient truly needs epi, they will already have a rapid heart rate as the first sign of shock. Their chest pain won't be caused by a hypertensive nature if they are truly entering the phases of anaphylaxis.

As far as I think I know, anaphylaxis is a hyper-immune response with a massive release of histamine causing increased cell wall permeability and vasodilation. The two of those together cause potentially high fluid loss to the extra-vascular space (edema), severe reduction in the lumen of the airway from inflammation and potentially major drop in BP. The HR increases in shock as the bodies primary means of maintaining blood pressure by moving the remaining fluid through the vessels at a faster rate.

From an ALS point of view, the treatment is going to be rapid fluid infusion to help the body maintain the pressure as with any shock.

If the patient gave themselves nitro and epi, then the nitro will probably hurt them a bit if they are entering decompensated shock but nitro wears off relatively fast and it will probably just make the epi a little less effective. 
Again someone correct me if anything I say is wrong. Im sure im not 100% correct.

As a provider, you should know better than to give nitro if you suspect anaphylaxis as the cause. Low pressure + high HR think shock.


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## systemet (Mar 23, 2012)

NYMedic828 said:


> I am sure someone with far more pharmacological knowledge will step in, but I really don't see 0.3mg of epi causing enough coronary constriction to case an MI.



Case report here (IV), also cites a couple of cases following SQ/IM administration.  http://www.cjem-online.ca/v8/n4/p289  Rare, but not impossible.



> If an elderly patient truly needs epi, they will already have a rapid heart rate as the first sign of shock. Their chest pain won't be caused by a hypertensive nature if they are truly entering the phases of anaphylaxis.



Not sure what you're saying here.  Not everyone needing IM epinephrine is hypotensive.  Some have uriticaria / angioedema + mild bronchospasm, or diarrhea / abdo cramping.


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## bigbaldguy (Mar 23, 2012)

systemet said:


> Case report here (IV), also cites a couple of cases following SQ/IM administration.  http://www.cjem-online.ca/v8/n4/p289  Rare, but not impossible.



Nice find!

 Sounds like epi causing this type of reaction is fairly rare but good to know that it is possible.


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## bstogner (Mar 30, 2012)

I am not positive but, I know that the paramedic protocols where I work have them take extreme caution administering epi for allergic Rxn to pts with a know cardiac Hx. They are normally advise diphenhydramine if the pt is not in shock.


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## Arovetli (Mar 30, 2012)

I also recall reading a case review on pubmed of IM epi causing a head bleed in an elderly pt. I'll try and find and post. Where I work we have to get OLMD orders for any epi administration for patients >65 yoa.


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## KellyBracket (Mar 31, 2012)

It is important to consider that anaphylaxis can be a cause of MI.

The risks of epinephrine are often over-blown. For example, one paper is titled "AMI after Administration of Low-Dose Intravenous Epinephrine for Anaphylaxis" (This is the case report that Systemet cites.) Except that the "low-dose" was *0.1 *mg IV, which is a pretty high frakin' dose. The only IV dose of epinephrine that has been used in a controlled study environment used *0.005-0.015* mg/minute as a starting dose. Roguemedic just did a column on this!

There are plenty of instance where anaphlaxis has been identified as the cause of STEMI, even in people without cardiac disease:
Acute coronary syndrome triggered by honeybee sting: a case report.
Acute anterior myocardial infarction after multiple bee stings. A case of Kounis syndrome.
Kounis syndrome presenting as ST-segment elevation myocardial infarction following a hymenoptera (bee) sting.


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## NYMedic828 (Mar 31, 2012)

KellyBracket said:


> It is important to consider that anaphylaxis can be a cause of MI.
> 
> The risks of epinephrine are often over-blown. For example, one paper is titled "AMI after Administration of Low-Dose Intravenous Epinephrine for Anaphylaxis" (This is the case report that Systemet cites.) Except that the "low-dose" was *0.1 *mg IV, which is a pretty high frakin' dose. The only IV dose of epinephrine that has been used in a controlled study environment used *0.005-0.015* mg/minute as a starting dose. Roguemedic just did a column on this!
> 
> ...



Not to change the subject, but if we consider giving 0.3mg IM or 0.1mg IV to patients as a HIGH dose. Who on earth decided that if someone is in arrest, we should give them upwards of 4mg IV?


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## Veneficus (Mar 31, 2012)

NYMedic828 said:


> Not to change the subject, but if we consider giving 0.3mg IM or 0.1mg IV to patients as a HIGH dose. Who on earth decided that if someone is in arrest, we should give them upwards of 4mg IV?



I am going to guess somebody who was doing the best they could with the knowledge they had at the time.

Most of the studies performed on any treatment came after the original resuscitation guidlines, which were based on the known theory at the time.

Like I keep saying, there is a major flaw with EBM, new practices or changes require far more evidence than the enshrined practices.

Even when somebody does a study and demonstrates treatment doesn't work, still more evidence is demanded. It never ends.


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