Antidote of methanol poisoning?

Appeared in: NORCET-7 Mains-2024

Explanation

Fomepizole is the primary antidote for methanol poisoning.
It functions as a competitive inhibitor of the enzyme alcohol dehydrogenase (ADH).
By blocking ADH, Fomepizole prevents the metabolic conversion of methanol into its highly toxic byproducts, formaldehyde and formic acid.
This action is crucial for preventing severe metabolic acidosis and irreversible optic nerve damage (blindness), which are the hallmarks of methanol toxicity.

Visual 1: Flowchart: Illustrating the metabolic pathway of methanol. The chart should show methanol being converted by alcohol dehydrogenase (ADH) to formaldehyde and then to formic acid, with a large 'X' indicating that Fomepizole blocks the ADH step.
Visual 2: Table: A comprehensive list of common poisons/drug overdoses and their specific antidotes, including opioids, benzodiazepines, heparin, warfarin, and acetaminophen.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Antidotes for specific poisons as background academic context rather than a clinical decision trigger.
Nurses must be able to rapidly identify signs of methanol poisoning (e.g., visual disturbances, altered mental status, deep and rapid breathing indicating acidosis) and prepare for the prompt administration of the correct antidote, Fomepizole.
Timely administration of Fomepizole is a critical nursing intervention that can prevent irreversible blindness and life-threatening acidosis.
What if? If Fomepizole is unavailable, the alternative treatment is an intravenous infusion of ethanol. The nurse's role would then involve carefully managing the ethanol infusion to maintain a therapeutic blood level, which requires frequent monitoring while also managing ethanol's own intoxicating and CNS depressant effects.

How to Approach the Question

First, identify the core of the question: it asks for the specific antidote to a named poison (methanol).
Recognize this as a factual recall question, which is common in pharmacology and toxicology sections of nursing exams.
Systematically review the options provided, recalling the primary indication for each drug.
Recall or deduce that Naloxone is for opioids, Protamine sulphate is for heparin, and Flumazenil is for benzodiazepines.
Through this process of elimination, Fomepizole remains as the correct answer for methanol poisoning.
Confirm this by remembering that Fomepizole is an inhibitor of alcohol dehydrogenase, the key enzyme in toxic alcohol metabolism.

Concept Tested & Keywords

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Practise the full NORCET-7 Mains-2024

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