At 2330, a client arrives in the emergency department after ingesting about 20 g of immediate-release acetaminophen at 2200. The client is alert, is protecting the airway, and has not vomited. The laboratory can report a serum acetaminophen level within 1 hour. Which prescription should the nurse implement now?

Quick answer
Activated charcoal now.

Why this is correct
The timing details decide the order. The ingestion was 90 minutes ago, so charcoal can still bind drug in the gut, and the client is alert with a protected airway, so it is safe to give. The 4-hour level will be drawn at 0200 and resulted by 0300, well within the 8-hour window for acetylcysteine.

Easy analogy or mental picture
Charcoal is a net you can only throw while the tablets are still in the stomach; acetylcysteine is the rescue team that can still arrive on time later.

Memory hook
Known time + early + alert airway = CHARCOAL now, LEVEL at 4 hours, NAC by 8 hours.

NCLEX decision rule
In poisoning questions, place each intervention on the timeline from ingestion and choose the one whose window is closing first.

Why the other choices are wrong
Starting acetylcysteine immediately is correct when the ingestion time is unknown or a level cannot be resulted before 8 hours, which is why it tempts, but here the level will be back in time. Drawing a level now is the right test at the wrong time: levels before 4 hours are uninterpretable on the Rumack-Matthew nomogram. Syrup of ipecac is still found in older teaching and home cabinets but is no longer recommended because vomiting delays charcoal and adds aspiration risk.