What is the primary treatment for acetaminophen (APAP) overdose when levels are above 150mg/dL at 4 hours after ingestion?

The primary treatment for acetaminophen (APAP) overdose, especially when levels are above 150 mg/dL at 4 hours post-ingestion, is N-acetylcysteine (NAC). NAC serves as a potent antidote for acetaminophen toxicity due to its ability to replenish glutathione stores in the liver, which are depleted in the process of metabolizing toxic metabolites of acetaminophen. The effectiveness of NAC is closely tied to its timing, with the best outcomes occurring when administered within 8-10 hours of the overdose.

Activated charcoal is often given in cases of overdose to reduce the absorption of the drug if the patient presents soon after ingestion; however, its combined use with NAC makes this approach particularly critical in managing acetaminophen toxicity. This combination helps to mitigate the risk of potential liver injury by addressing both the ongoing absorption of the toxin and providing a specific antidote.

The other treatments mentioned do not specifically target acetaminophen toxicity. Flumazenil is a benzodiazepine antagonist and is not indicated for acetaminophen overdose. Sodium bicarbonate may be useful in certain types of acid-base disturbances but is not relevant for treating acetaminophen toxicity. Supportive care is crucial in any overdose scenario