A teenager ingests a handful of acetaminophen. Which statement is true?

An acetaminophen level drawn at hour four is a critical time point in the assessment of acute acetaminophen ingestions because it aligns with the hepatotoxicity risk timeline. The standard clinical practice includes measuring the acetaminophen level at various intervals after ingestion, and the four-hour mark is particularly significant because it allows for the determination of the peak concentration in the bloodstream when toxicity could start manifesting.

This timing is essential as it helps clinicians decide whether the patient requires antidotal therapy with N-acetylcysteine (NAC). The Rumack-Matthew nomogram is often used in this context, which takes the acetaminophen level at four hours post-ingestion to guide treatment decisions. If the level is above the treatment threshold on the nomogram, initiating NAC therapy becomes critical to prevent potential liver damage.

In contrast, while liver function tests can provide valuable information about hepatic injury, they are not always necessary in every case of acetaminophen ingestion right away, particularly if the acetaminophen level is below the toxic threshold. Renal sequelae are not a common expected outcome of acetaminophen toxicity, as the primary concern is mainly hepatic. Lastly, concerns regarding the safety of the oral versus intravenous formulation of NAC revolve around