Acetaminophen is one of the most common pharmaceutical ingestions in overdose and a leading cause of acute of liver failure in the U.S.  Early recognition and treatment is critical for prevention of morbidity.

• Vigilance and screening is required for this "silent poison", available in hundreds of OTC products and in combination with numerous prescription medications. Symptoms may not be present early in course (for up to 24 hours) in poisoning.
• Maximal benefit with antidote treatment, n-acetylcysteine (NAC) is time dependent within 8 hours of ingestion. Fulminant hepatotoxicity is unusual in acute overdoses treated with NAC within 10 hours of ingestion.
• Early prediction of poor prognosis is essential to identify patients who may require life-saving liver transplantation.  Kings College Criteria: Arterial pH less than 7.30, INR greater than 6.5, Creatinine greater than 3.4, Grade III or IV encephalopathy combined with Lactate greater than 3.5 and Phosphate greater than 3.75 may increase sensitivity.

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