Paracetamol Overdose N-AcetylCysteine Adverse Reaction

[old pal grover]

Hi,
A patient is admitted following paracetamol OD. An N-acetylcysteine infusion is started but the patient develops a rash and wheeze.

How would you manage this patient?

Page 30 of the BNF states "hypersensitivity-like reactions managed by reducing the infusion rate or suspending until reaction settled", "rash also managed by giving antihistamines; acute asthma managed by giving short acting beta 2 agonist"

But I am unsure if this reaction should be managed as anaphylaxis using adrenaline?

Thanks!

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[jdh71]

But I am unsure if this reaction should be managed as anaphylaxis using adrenaline?

Thanks!

No. Because it is not anaphylaxis.

 

[old pal grover]

Initially I did not think this was anaphylaxis - but when I looked it up it said to treat as anaphylaxis if there were 2 of the following : the reaction started within minutes/hrs of allergen (which it did), if their are skin changes (rash) and/or if there are ABC difficulties (possibly wheeze?).

So how do you know when to treat something like this as anaphylaxis and when not to?

 

[Rendar5]

Hi,
A patient is admitted following paracetamol OD. An N-acetylcysteine infusion is started but the patient develops a rash and wheeze.

How would you manage this patient?

Page 30 of the BNF states "hypersensitivity-like reactions managed by reducing the infusion rate or suspending until reaction settled", "rash also managed by giving antihistamines; acute asthma managed by giving short acting beta 2 agonist"

But I am unsure if this reaction should be managed as anaphylaxis using adrenaline?

Thanks!

anaphylaxis is not a simple allergic reaction. You're gonna see wheezing, hypotension, possible angioedema,etc. Not just a rash. Hypotension is the big one because we're talking shock. Then go for the epi. Otherwise, what's the point of using the epinephrine. If you just have rash and a slight wheeze, and you think you have plenty of time, slow the infusion rate or stop it and treat with albuterol (or whatever they use over there) and an antihistamine (careful in the elderly). At that point you're using your clinical judgment and not the textbook.

Also keep in mind that infusion rate reactions can occur with a variety of agents including vancomycin (Red Man Syndrome) and as they are a result of sensitivity , can be treated just by rate adjustment.

 

[old pal grover]

Thanks for the really helpful reply