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.

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.