Tylenol toxicity...PK question

[nagoyankitty]

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So...if I have a patient who took unknown amount of tylenol and the serum concentration is 10 (way below toxic level) and this was measured 5 hours post ingestion, can we figure out how much she took 5 hours ago?

 

[Dred Pirate]

Do you understand how half lives work? Look it up - should be pretty easy to determine what her level was immeidately post ingestion - then use bioavailability and Vd to estimate mg ingested

 

[npage148]

Was it apap er, do od alter normal absorption, bezoar?

 

[Ackj]

This sounds more like you're doing detective work to solve a missing # of tablets, rather than going for overdose treatment stuff. Thanks to how common the latter is, there's a fair amount of PK data for APAP, so you could get a pretty good idea with the way Dred suggested. I'm not convinced it will tell you exactly how many tablets though, because you're going to have some variability using PK parameters.

 

[njac]

If only it were a 4 hour level...
There just might be a paper out there for that 😉

(Would also need patient weight for that paper to work)