# A 17-year-old client weighing 58 kg is brought to the emergency department at 0700. The client reports taking forty 500-mg acetaminophen tablets at about 2100 the previous evening after an argument with a partner. The client is alert, reports nausea, and denies other ingestions. A serum acetaminophen level, AST, ALT, and INR were drawn at 0715 and are pending. Which actions should the nurse anticipate? Select all that apply. > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=617270&lang=en > language: en > subject: Accident/Error/Injury Prevention > category: SIPC ## Question A 17-year-old client weighing 58 kg is brought to the emergency department at 0700. The client reports taking forty 500-mg acetaminophen tablets at about 2100 the previous evening after an argument with a partner. The client is alert, reports nausea, and denies other ingestions. A serum acetaminophen level, AST, ALT, and INR were drawn at 0715 and are pending. Which actions should the nurse anticipate? Select all that apply. 1 Recheck the level and ALT before stopping the acetylcysteine 2 Assign a staff member for continuous one-to-one observation 3 Arrange psychiatric transfer once the first ALT result is normal 4 Start IV acetylcysteine before the laboratory results return 5 Hold acetylcysteine until the level is plotted on the nomogram 6 Give activated charcoal 50 g by mouth as soon as possible ## Explanation The ingestion was about 345 mg/kg and occurred about 10 hours before arrival, so acetylcysteine is started without waiting for the level, because its protective benefit falls sharply after 8 hours. The intentional overdose requires continuous one-to-one observation, and acetylcysteine is stopped only after a repeat level and ALT confirm it is safe. Charcoal is useful mainly within about 1 to 2 hours of ingestion, and a normal first ALT does not exclude liver injury, which peaks days later. ## In-depth explanation Quick answer Start acetylcysteine now, keep one-to-one observation, and recheck the level and ALT before stopping acetylcysteine (options 4, 2, 1). Why this is correct Calculate: 40 x 500 mg = 20 g, or about 345 mg/kg in a 58-kg client, well above the 150 mg/kg toxic threshold. The time is 0700 and the ingestion was at 2100, so about 10 hours have passed. After 8 hours, acetylcysteine is started immediately and not delayed for the nomogram. Treatment is continued or stopped based on a repeat acetaminophen level and ALT at the end of the infusion. The ingestion followed an argument and was intentional, so constant observation is needed for safety. Easy analogy or mental picture Acetylcysteine is like refilling the liver's protective sponge (glutathione): once the spill has been soaking for 8 hours, you refill now instead of waiting to measure the puddle. Memory hook Over 8 hours and a toxic dose: treat first, measure second. NCLEX decision rule When a time-sensitive antidote loses benefit with delay and the history already shows a toxic dose, start the antidote before confirmatory results. Why the other choices are wrong Holding acetylcysteine for the nomogram (option 5) is tempting because the 4-hour level and nomogram are the textbook sequence, but that sequence applies when the client presents early; past 8 hours with a toxic history, waiting costs liver protection. Activated charcoal (option 6) is a correct decontamination step for a recent ingestion, but at 10 hours little drug remains in the gut and it adds aspiration risk for a nauseated client. Transfer after a normal first ALT (option 3) is tempting because the client looks well, but transaminases rise over 24 to 72 hours, and a normal early value does not end medical treatment. References 1StatPearls: Acetaminophen ToxicityToxic dose threshold, starting NAC without waiting when presentation is delayed, timing of charcoal and liver enzyme peak ## Clinical scenario Scenario An adolescent presents about 10 hours after an intentional ingestion of 20 g of acetaminophen (about 345 mg/kg); initial laboratory results are pending. ## Key concepts - **Acetylcysteine (NAC)** — The antidote for acetaminophen toxicity that restores glutathione and is most protective when started within 8 hours. - **Rumack-Matthew nomogram** — A graph of serum acetaminophen level against hours since a single acute ingestion, valid from 4 to 24 hours, used to decide on treatment. - **Hepatotoxicity** — Liver cell injury from the toxic metabolite NAPQI; enzyme levels typically peak 72 to 96 hours after ingestion. ## Related questions - [A circulating nurse leads the final time-out for an operative procedure. 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