N-acetylcysteine is useful for treatment of toxicity due to:
**Core Concept**
N-acetylcysteine (NAC) is an antioxidant supplement that replenishes glutathione stores in the body, thereby reducing oxidative stress. It is particularly useful in the management of acetaminophen (paracetamol) overdose, which leads to severe liver damage due to the formation of a toxic metabolite.
**Why the Correct Answer is Right**
NAC works by replenishing glutathione, the body's primary antioxidant, which is depleted in the setting of acetaminophen overdose. Glutathione conjugates the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), thereby reducing its hepatotoxic effects. NAC also has mucolytic properties, which can help in the treatment of conditions like chronic obstructive pulmonary disease (COPD).
**Why Each Wrong Option is Incorrect**
**Option A:** N-acetylcysteine is not primarily used for the treatment of digoxin toxicity. Digoxin toxicity is managed with digoxin-specific antibody fragments (Fab fragments).
**Option B:** N-acetylcysteine is not effective in the treatment of theophylline toxicity. Theophylline toxicity is managed with activated charcoal and supportive care.
**Option C:** N-acetylcysteine is not used for the treatment of salicylate toxicity. Salicylate toxicity is managed with activated charcoal, supportive care, and hemodialysis in severe cases.
**Clinical Pearl / High-Yield Fact**
In the setting of acetaminophen overdose, NAC should be administered within 8-10 hours of ingestion for optimal benefit. Early administration of NAC can significantly reduce the risk of liver failure and mortality.
**Correct Answer: A. Acetaminophen (paracetamol) overdose**