A patient who has received heparin for prophylaxis against deep venous thrombosis (DVT) is bleeding. Which of the following is the antidote for a patient with an overdose of heparin?

1. A

   Protamine Sulphate

2. B

   Vitamin K

3. C

   Atropine Sulphate

4. D

   Phytotretamine

Appeared in: RML 2023

Explanation

• Protamine Sulphate is the specific and rapid-acting antidote for heparin overdose.
• It is a strongly basic (positively charged) protein that directly binds to the acidic (negatively charged) heparin molecule.
• This binding forms a stable, inactive complex, which immediately neutralizes heparin's anticoagulant effect.
• The standard neutralizing dose is approximately 1 mg of protamine sulphate for every 100 units of heparin.

Why Other Options Were Wrong

• Option B: Vitamin K is the antidote for warfarin (an oral anticoagulant), not heparin. It acts by restoring the synthesis of clotting factors in the liver, which is a much slower process and does not affect heparin.
• Option C: Atropine Sulphate is an anticholinergic agent. It is used to treat symptomatic bradycardia and as an antidote for organophosphate poisoning. It has no effect on the coagulation cascade.
• Option D: Phytotretamine is not a recognized medication or antidote in standard pharmacology. It is included as a plausible-sounding but incorrect option (a distractor).

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Pharmacology: Antidotes for Anticoagulant Overdose to guide bedside assessment, documentation, and the next nursing action.
• Nurses must be able to promptly recognize signs of anticoagulant overdose (e.g., hematuria, melena, petechiae, unexplained bruising) and know the specific antidote for each medication.
• Administering the wrong antidote is a critical medication error. Giving Vitamin K for heparin overdose would not stop the bleeding and would dangerously delay the correct treatment with protamine sulphate.
• Protamine sulphate must be administered slowly via IV infusion, as rapid injection can cause severe hypotension, bradycardia, and anaphylactoid reactions.

How to Approach the Question

• First, identify the key information in the clinical scenario: the drug administered is 'heparin', the adverse event is 'bleeding', and the question asks for the 'antidote'.
• This is a direct recall question testing your knowledge of pharmacology.
• Mentally access your knowledge of common anticoagulants and their specific reversal agents.
• Recall that heparin is an acidic molecule and its effects are reversed by a basic molecule. Protamine Sulphate is the specific antidote for heparin.
• Systematically evaluate the other options to confirm your choice. Vitamin K is for warfarin. Atropine is for bradycardia or poisoning. Phytotretamine is an unfamiliar term, making it a likely distractor.
• Conclude that Protamine Sulphate is the only correct and specific antidote for heparin-induced bleeding.

Concept Tested & Keywords

• Concept Tested: Pharmacology: Antidotes for Anticoagulant Overdose
• Stem keywords: heparin, deep venous thrombosis (DVT), bleeding, antidote, overdose
• Lead-in keywords: Which of the following
• Clinical cues: Patient received heparin for DVT prophylaxis and is now bleeding, indicating an overdose or adverse reaction.

Question ID

QKcFQDw4hghsblt79sSa81

Copy ID

Reference Book

E6 Pharmacology Nursing Lilley 11e Part 2 pp. 108-110, 123-125

E6 Pharmacology KD Tripathi Essentials 9e Part 2 p. 291-293