Stages of Acute Acetaminophen Poisoning

Stage

Time Postingestion

Description

I

0–24 hours

Anorexia, nausea, vomiting

II

24–72 hours

Right upper quadrant abdominal pain (common)

AST, ALT, and, if poisoning is severe, bilirubin and PT (usually reported as the INR) sometimes elevated

III

72–96 hours

Vomiting and symptoms of liver failure

Peaking of AST, ALT, bilirubin, and INR

Sometimes renal failure and pancreatitis

IV

> 5 days

Resolution of hepatotoxicity or progression to multiple organ failure (sometimes fatal)

AST = aspartate aminotransferase; ALT = alanine aminotransferase; INR = international normalized ratio; PT = prothrombin time.