Antidote of Paracetamol (PCM) poisoning is:

Appeared in: RML MAINS 2025

Explanation

N-Acetylcysteine (NAC) is the specific and effective antidote for poisoning caused by paracetamol (acetaminophen).
In an overdose situation, the normal metabolic pathways for paracetamol become saturated, leading to the formation of a highly toxic metabolite called N-acetyl-p-benzoquinone imine (NAPQI).
This toxic metabolite, NAPQI, depletes the liver's natural stores of glutathione, an antioxidant that normally neutralizes it.
N-Acetylcysteine works by acting as a precursor to glutathione, replenishing the liver's supply. This restored glutathione then neutralizes the toxic NAPQI, preventing it from causing severe liver cell damage and failure.

Option B: Protamine sulphate is an antidote, but it is used to reverse the effects of heparin, not paracetamol. It has no effect on paracetamol toxicity.
Option C: Warfarin is not an antidote; it is an oral anticoagulant (blood thinner) used to prevent the formation of blood clots.
Option D: Vitamin K is the specific antidote for an overdose of oral anticoagulants like warfarin, not paracetamol.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Antidotes for common poisonings as background academic context rather than a clinical decision trigger.
Timely administration of N-acetylcysteine is critical. Its effectiveness is highest when started within 8 hours of paracetamol ingestion, significantly reducing the risk of liver failure.
Nurses are responsible for accurately assessing the time and amount of ingestion, preparing and administering the NAC infusion according to protocol, and closely monitoring the patient for signs of liver failure (e.g., jaundice, altered mental status) and adverse reactions to NAC (e.g., anaphylactoid reactions).
What if? If a patient presents with paracetamol poisoning more than 24 hours after ingestion, the efficacy of N-acetylcysteine is significantly reduced. The primary focus of care shifts to supportive management of acute liver failure, and the patient may be evaluated for an urgent liver transplant.

How to Approach the Question

First, identify the core of the question. It is asking for the specific antidote for paracetamol (PCM) poisoning.
Recognize this as a factual recall question from pharmacology, a common topic in nursing exams.
Systematically review each option based on your knowledge of common drugs and their antidotes.
Recall that N-Acetylcysteine is the standard, evidence-based treatment for paracetamol overdose.
Eliminate the other options by correctly identifying their primary roles: Protamine sulphate reverses heparin, Vitamin K reverses warfarin, and warfarin is an anticoagulant itself.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 158-160

E6 Pharmacology Katzung 16e p. 103-105

Practise the full RML MAINS 2025

Attempt every question from this paper in a timed mock, then review the full solution for each one.