Multiplying the serum aminotransferase by the acetaminophen concentration to predict toxicity following overdose

Abstract

The APAP × AT multiplication product, calculated at the time of presentation and after several h of antidotal therapy, holds promise as a new risk predictor following APAP overdose. It requires neither graphical interpretation nor accurate time of ingestion, two limitations to current risk stratification.

When do the aminotransferases rise after acute acetaminophen overdose?

“…8,23,[30][31][32] We believe that risk prediction involves comparing both the (falling) serum APAP and the (rising) serum AT and have proposed a simple method for doing so. 33 This study is purely a descriptive analysis, and not a comparative study. We did not analyze the rate of AT changes in patients with peak concentrations below 1,000 IU/L.…”

The NACSTOP Trial: A Multicenter, Cluster‐Controlled Trial of Early Cessation of Acetylcysteine in Acetaminophen Overdose

“…No subjects met the primary outcome of hepatic injury (OR 1.0 [95% CI 0.02, 50]). There was no significant difference in 20-hour ALT between intervention and control groups (median 18 IU/L [13,22] versus 16 [13,21], P = 0.51) ( Fig. 4) No subjects required an extension in acetylcysteine treatment.…”

“…We required that they have, by definition, a 12‐hour APAP × ALT product below 800 mg/L × IU/L, ( ) a value substantially lower than is seen in patients who go on to develop hepatotoxicity or hepatic failure. ( ) Other risk stratification measures were also reassuring in these patients: The ψ parameter at the start of treatment was generally less than or equal to 2 mmol/L × hour, ( ) and the serum acetaminophen concentration almost always had fallen by at least 90% in 12 hours.…”

Changing the Management of Paracetamol Poisoning

“…A high product of paracetamol concentration and concurrent ALT might also predict hepatic injury in those who are treated with acetylcysteine, but its utility in defining need for therapy has not been tested. 36 Changes in international normalized ratio are a more sensitive measure of hepatic injury, but changes in international normalized ratio follow liver injury, and they are useful in estimating recovery from liver injury rather than predicting risk earlier. 4 Renal failure is rare, so it is not useful as a screening measure, but at presentation it predicts poor outcome.…”