Antidote of heparin overdose?

Appeared in: NORCET-7 Mains-2024

Explanation

Protamine sulphate is the specific pharmacological antagonist for unfractionated heparin.
It functions as an antidote through a chemical neutralization reaction.
Protamine is a highly basic, positively charged peptide that binds to the acidic, negatively charged heparin molecule.
This binding forms a stable, inactive salt complex, which has no anticoagulant activity, effectively reversing heparin's effects.
The standard neutralizing dose is approximately 1 mg of protamine for every 100 units of heparin remaining in the body.

Option A: Naloxone is an opioid antagonist and has no effect on the coagulation cascade or heparin.
Option B: Fomepizole is an alcohol dehydrogenase inhibitor and is unrelated to anticoagulants.
Option D: Vitamin K is the antidote for warfarin, not heparin. These two anticoagulants have different mechanisms of action and different reversal agents.

Visual 1: Table: Common Antidotes - A quick reference table listing common toxins/overdoses (e.g., Heparin, Warfarin, Opioids, Benzodiazepines, Acetaminophen) and their corresponding antidotes.
Visual 2: Diagram: Heparin-Protamine Neutralization - A simple visual showing the positively charged protamine molecule binding to the negatively charged heparin molecule to form an inactive, neutral salt.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological Antidotes for Anticoagulants as background academic context rather than a clinical decision trigger.
Knowing the correct antidote is a critical patient safety competency for nurses, as rapid reversal of anticoagulation can be life-saving in cases of severe bleeding.
Nurses must administer protamine sulfate slowly via IV, as rapid infusion can cause severe hypotension, bradycardia, and anaphylactoid reactions.
What if? If the overdose was from a low-molecular-weight heparin (LMWH) like enoxaparin, protamine sulfate would only provide partial reversal of the anti-Xa activity, and the patient would require closer monitoring for bleeding.

How to Approach the Question

This is a factual recall question from pharmacology.
First, identify the key drug in the question: 'heparin'.
Next, identify the clinical problem: 'overdose'.
The question asks for the 'antidote'. Your task is to retrieve the specific antagonist for heparin from your knowledge base.
Mentally review the common anticoagulants and their antidotes. Heparin's antidote is protamine sulfate. Warfarin's antidote is Vitamin K.
Evaluate the other options to confirm they are incorrect. Naloxone is for opioids, and Fomepizole is for toxic alcohol poisoning.

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.