PCN allergy and Ancef

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epidural man

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The last time I looked at it, I remember reading that if you are allergic to PCN, you are actually much more likely to have a reaction to Clinda.

I think the most recent data is 0.7% overall cross reactivity (Ancef/PCN), and 3% if the PCN allergy is proven to be a true allergy.

Regardless, the practice of not using Ancef when PCN allergy is listed is ridiculous.

BUT -
Because of institutional pressures, I still go along with clinda substitution if that train is already started. (If it’s up to me, I’ll just give the Ancef).

In fact, I just gave Ancef in a PCN allergic patient and the PACU nurse gave me crap., so it’s just easier to live the dogma.

I’m just curious - how many of you are emohatic about it and just always give the Ancef, or what is your practice?o

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We just give ancef. There were a few studies that showed cross reactivity wasn't a real issue and it was chalked up to possible manufacturing contamination back in the day.

Also was some literature showing higher joint infection rates when patients were given second line antibiotics (vanco, clinda)

So we determined that the real risk of infection was more problematic than the unlikely risk of cross reactivity.

That being said, if a patient has a true recent anaphylaxis to PCN, we might avoid it. But 95% of the pcb allergies are just remote history or unknown reactions
 
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The last time I looked at it, I remember reading that if you are allergic to PCN, you are actually much more likely to have a reaction to Clinda.

I think the most recent data is 0.7% overall cross reactivity (Ancef/PCN), and 3% if the PCN allergy is proven to be a true allergy.

Regardless, the practice of not using Ancef when PCN allergy is listed is ridiculous.

BUT -
Because of institutional pressures, I still go along with clinda substitution if that train is already started. (If it’s up to me, I’ll just give the Ancef).

In fact, I just gave Ancef in a PCN allergic patient and the PACU nurse gave me crap., so it’s just easier to live the dogma.

I’m just curious - how many of you are emohatic about it and just always give the Ancef, or what is your practice?o
Who cares what a damn PACU nurse thinks it appropriate? ABX are NEVER a nursing decision. Surgeons order ABX for surgical pts. Our OR pharmacists will flag anything if they have a question.

We give Ancef all the time to PCN-allergic patients. ONLY if they've had a life-threatening reaction to PCNs do we give something else. If they tell us "I had PCN when I was a little kid and my mom said I was allergic" then we give Ancef. If they tell us "My throat swelled up and I nearly died" then we won't.
 
Cephalosporin cross reactivity in PCN allergic patients is exceedingly low, less than 1%. Obviously the more severe the PCN allergy it stands to reason may predict a more vigorous immune response and hence cross reaction. We have been told by ID to avoid using clinda because it is not effective and instead use vanco for concern for skin flora.



Also I have seen C diff from clinda and it isn’t pretty. One lady ended up with a stool transplant.
 
No cross reactivity except for Type 4 hypersensitivity (T-cell mediated Steven Johnson syndrome).

Other cephalosporins have some cross allergenicity. There is a chart out there that shows cross allergenicity.
 
One lady ended up with a stool transplant.
That is such a nasty concept - could hardly believe it when we first did one. I swear one of our GI docs was downright proud that he was the donor. We were just grossed out.
 
That is such a nasty concept - could hardly believe it when we first did one. I swear one of our GI docs was downright proud that he was the donor. We were just grossed out.

My wife’s friend was the donor for her mom. I guess it is done by first screening the stool and then it is made into some slurry and placed via NG tube.
 
Had a CRNA years ago give cefazolin to a patient with a history of an anaphylactic reaction to PCN. Guess what happened during the case...

Hint, lots of epi was involved.
 
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Better than a total colectomy. Seen that a few times...

As a med student on my surgery rotation we had a very virulent strain of C diff going through the ICU. We had one patient who received a pre op dose of antibiotics and developed diarrhea on POD1. He was septic by afternoon and passed that night. Had several patients pass or require colectomies in a four week stretch. It was horrific.
 
As a med student on my surgery rotation we had a very virulent strain of C diff going through the ICU. We had one patient who received a pre op dose of antibiotics and developed diarrhea on POD1. He was septic by afternoon and passed that night. Had several patients pass or require colectomies in a four week stretch. It was horrific.
This is why surgeons and proceduralists need to be more cognizant of the side effects of these not benign drugs and practice abx stewardship. One pain guy I work with asks for abx for all his cervical ESI or MBB or if they are even remotely diabetic. Then most others don't care at all for abx and inject away.
 
Do not withhold ancef from ppl with PCN allergies, please. The R side chain of ancef is not cross reactive with penicillin.

Penicillin vs 1st and 2nd Generation Cephalosporin Anitbiotics Image.png

 
I just had a patient who coded, had ST elevations everywhere on monitor. Got a stat ECG, which showed STEMI. got him to cath lab, clean coronaries. Later found out to be anaphylaxis to PCN, even though he's had like 7-8 recent similar surgeries with ancef...it had to be my time he went complete allergic reaction! i guess it's true, it doesn't even have to be the first time but can be repeated exposure.
 
I just had a patient who coded, had ST elevations everywhere on monitor. Got a stat ECG, which showed STEMI. got him to cath lab, clean coronaries. Later found out to be anaphylaxis to PCN, even though he's had like 7-8 recent similar surgeries with ancef...it had to be my time he went complete allergic reaction! i guess it's true, it doesn't even have to be the first time but can be repeated exposure.
How much epi did he get?
 
We are a major total joint site so the surgeons hate not being able to use ancef. Our guidelines:

BS PCN reaction - give ancef
SJS/TEN - alternate
Anaphylaxis/airway issues - allergist consult, alternate abx if unable

We occasionally will do a test dose of ancef for questionable history.

Part of the issue, at least the last time we checked, is that the infectious disease society is still recommending alternate abx for pcn allergic patients. So at the board meeting when we were discussing this issue there were some legal concerns since ancef is still a leading cause of periop anaphylaxis. So if it was given and a patient has a PCN allergy on their chart regardless of reaction could we be sued? Unfortunate that we have to think this way sometimes.
 
Had a CRNA years ago give cefazolin to a patient with a history of an anaphylactic reaction to PCN. Guess what happened during the case...

Hint, lots of epi was involved.
Well, cross IgE-mediated cross-allergenicity of cephazolin and penicillin. is not supported by the literature. That isn't to say that you can't be independently allergic to both cephazolin and Pen VK for example but evidence-based practice still permits dosing cephazolin in patients who have anaphylaxis to Penicillin.
 



 
Had a neighbor who was an allergist. Got so many referrals from surgeons after patient "had a penicillin allergy" to see if they could get ancef. Not only did his clinic confirm what has already been reported that there is slight to no cross reactivity between ancef and penicllin, but kids that "had an allergic reaction" as a child didn't even have an allergy to penicillin.

We give ancef to almost everyone, especially ortho, because ancef has been shown to be superior to other abx for their cases.
 
We just give ancef.
Occasionally a surgeon wants clinda instead.
So I give clinda and comment PSR.
(Per Surgeon Request)
All surgical antibiotics in our shop are ordered by the surgeon pre-operatively, and usually hanging on the stretcher IV pole when we go to pre-op for the handoff. We don't note PSR because they're always and only PSR.
 
Great stuff in this thread.

Just wanted to add periopdoc comment from a few years ago as reference…

Cross reactivity between Penicillin and Cephalosporins is largely a theoretical construct that is not borne out by the evidence. The initial studies that produced the 10% cross reactivity rate were flawed in that early preparations of cephalosporins were contaminated with small amounts of penicillin, and early preparations of penicillin were contaminated with small amounts of cephalosporins.

More recent studies fail to support the claimed cross reactivity and, in fact, demonstrate that cross reactivity between penicillin and cephalosporins is lower than cross reactivity between penicillin and other antibiotics. Primary cephalosporin allergy runs about 1-3% in the general population. Penicillin allergic patients are 3x more likely to be allergic to unrelated antibiotics. The supposed cross reactivity is, mostly, a reflection of the fact that Pen allergic patients are more likely to have primary allergic reactions to other medications too, superimposed on the expected rate of reaction in the general population.

After introduction into the body, the penicillin beta-lactam ring remains stable while the cephalosporin ring is immediately degraded. Any type of cross reactivity is more likely due to side chain similarity.

So, the wise thing to do is to avoid cephalosporins with similar side chains in patients with documented typical IgE mediated reactions, and patients with documented IgE penicillin antibodies. For patients with mild reactions, or undocumented reactions, the use of cephalosporins is not contraindicated and is medico-legally and morally defensible.

- bsd
 
I'm usually not told which antibiotic to give at the hospitals I work at, so I choose.

I give cefazolin even for patients with anaphylaxis to other first-generation cephalosporins and have never had a problem. As others have said, the allergic reaction appears to not be due to the beta-lactam ring, but the R-side chain, of which cefazolin's is unique.

Here's a good discussion on the subject, including a table.
 
How much epi did he get?
So it’s sort of a rhetorical question because I saw it once myself. Hemodynamic collapse, give epi, ST changes, clean cath. Chalk it up to the epi rather than CAD.
 
So it’s sort of a rhetorical question because I saw it once myself. Hemodynamic collapse, give epi, ST changes, clean cath. Chalk it up to the epi rather than CAD.

I’ve seen tombstone ST elevations and SBP in the 40s after ancef but before giving epi. When BP was restore (with epi), the ST segments came down. That patient also had a clean Cath.
 
I’ve seen tombstone ST elevations and SBP in the 40s after ancef but before giving epi. When BP was restore (with epi), the ST segments came down. That patient also had a clean Cath.

Same.
 
Recently, Macy and Contreras31 demonstrated in a large database study including more than 1.5 million patients that when cephalosporins were administered to patients with reported penicillin allergies, the incidence of new allergic reactions was only 1%, and the incidence of anaphylaxis was 0% per cephalosporin course.

Of note, using β-lactams with different side-chain structures does not completely exclude a possible allergic reaction but may reduce the chance. For instance, in case of a reported penicillin allergy with only skin symptoms, e.g., rash, cefazolin can be administered for perioperative prophylaxis with low risk.

In case of avoiding all β-lactam antibiotics, most guidelines recommend clindamycin or vancomycin for Gram-positive cover, an aminoglycoside or fluoroquinolone when Gram-negative cover is needed, and metronidazole in case surgery is performed in an area with anaerobic flora.9
 
Recently, Macy and Contreras31 demonstrated in a large database study including more than 1.5 million patients that when cephalosporins were administered to patients with reported penicillin allergies, the incidence of new allergic reactions was only 1%, and the incidence of anaphylaxis was 0% per cephalosporin course.

Of note, using β-lactams with different side-chain structures does not completely exclude a possible allergic reaction but may reduce the chance. For instance, in case of a reported penicillin allergy with only skin symptoms, e.g., rash, cefazolin can be administered for perioperative prophylaxis with low risk.

In case of avoiding all β-lactam antibiotics, most guidelines recommend clindamycin or vancomycin for Gram-positive cover, an aminoglycoside or fluoroquinolone when Gram-negative cover is needed, and metronidazole in case surgery is performed in an area with anaerobic flora.9
You didn't read the thread did you?
 
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