In the Emergency Department, we often screen for acetaminophen toxicity for patients who may have ingested substances as a suicide attempt. We check the serum acetaminophen level 4 hours post-ingestion. Occasionally, we are surprised by a toxic level because in the first 24 hours, because symptoms are can be mild and nonspecific (abdominal pain, nausea, lethargy).
- The toxic ingestion dose of acetaminophen is 150 mg/kg.
- The serum acetaminophen level when N-acetylcysteine treatment should be started is 150 mcg/mL (see Rumack Matthew nomogram)
- The starting IV dose of N-acetylcysteine is 150 mg/kg over 15 minutes.
References
Larson AM. Acetaminophen hepatotoxicity. Clin Liver Dis. 2007 Aug;11(3):525-48, vi. .
Hi Michelle. No poison center or toxicologist uses oral N-Ac for 72 hrs anymore. 20 hours needed only
ReplyDeleteHey @SFTox: Thanks for catching this. This is a good review article, but it's from 2007. Agreed that for uncomplicated overdoses, only 20 hours is needed. Will need more doses if levels still rising though. So I changed the wording to say "may need as many as 17 doses". Good catch!
ReplyDeleteThe Tox curmudgeon says that at the end of the initial N-Ac tx by oral or IV N-Ac, if AST/ALT are rising or [apap] is still detectable, N-Ac must continue indefinitely, by either route... I would leave out the "17 doses" altogether.
ReplyDeleteMichelle:
ReplyDeleteMost toxicologists would recommend giving the first dose of IV N-Ac (150 mg/kg) over one hour (rather than 15 minutes) to minimize the chance of an anaphylactoid reaction. In fact, this is now the official recommendation.
Good call @SFTox and Leon. One of the down sides of summarizing a review article from 2007 is outdated info. Thanks guys. Will change the card.
ReplyDelete