What is the antidote of heparin overdose?

Appeared in: NORCET 6 mains-2024

Explanation

Protamine sulphate is the specific pharmacological antagonist for heparin.
It is a strongly basic, positively charged peptide that binds ionically to the acidic, negatively charged heparin molecule.
This binding forms a stable, inactive complex, which neutralizes the anticoagulant effect of heparin.
The reversal of heparin's effects by protamine sulphate is rapid, typically occurring within 5 minutes of intravenous administration.

Option A: Naloxone is an opioid antagonist and has no effect on heparin.
Option C: Activated charcoal works by adsorbing substances in the gastrointestinal tract and is ineffective for drugs administered parenterally (like IV heparin).
Option D: Deferoxamine is a chelating agent that binds to iron; it does not interact with heparin.

Visual 1: Diagram: Illustrating the chemical binding of positively charged protamine to negatively charged heparin, forming an inactive salt complex.
Visual 2: Table: A comprehensive list of common poisons/drugs and their specific antidotes used in clinical practice.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological Antidotes as background academic context rather than a clinical decision trigger.
A core nursing responsibility during heparin therapy is monitoring the activated Partial Thromboplastin Time (aPTT) to maintain therapeutic anticoagulation and prevent overdose. The target is usually 1.5 to 2.5 times the control value.
Patient safety protocols mandate that protamine sulphate must be readily accessible in any clinical area where heparin is administered, especially as a continuous infusion.
Nurses must educate patients on bleeding precautions, such as using a soft toothbrush and an electric razor, and reporting any signs of unusual bleeding or bruising immediately.

How to Approach the Question

First, identify the key drug in the question stem, which is 'heparin'.
Next, understand the core of the question, which is asking for the 'antidote' or reversal agent for this specific drug.
This is a factual recall question common in pharmacology. Access your knowledge about anticoagulants and their specific antagonists.
Evaluate the given options: Naloxone (opioids), Protamine sulphate (heparin), Activated charcoal (oral toxins), Deferoxamine (iron).
Match the drug (heparin) with its known, specific antidote (Protamine sulphate).
Confirm the other options are incorrect by recalling what substances they are used to counteract.

Concept Tested & Keywords

QNHuXeNbrg-P7-FAhZGjMd

Practise the full NORCET 6 mains-2024

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