Anticoagulants: low molecular weight heparin: practice question

A Pharmacology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pharmacology · Anticoagulants: low molecular weight heparin

Sample item

Compared with unfractionated heparin, enoxaparin has which characteristic?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Predominant anti-Xa activity with predictable weight-based dosing and no routine aPTT monitoring

Low molecular weight heparins are too short to bridge antithrombin to thrombin, so they act chiefly on factor Xa and have a predictable dose response with better bioavailability. Anti-Xa levels are checked only in special groups such as renal failure or pregnancy.

Option by option

  • A. Predominant anti-Xa activity with predictable weight-based dosing and no routine aPTT monitoring (correct)

    Correct. Anti-Xa predominance and predictable dosing define LMWH.

  • B. Predominant antithrombin activity requiring aPTT monitoring

    That describes unfractionated heparin.

  • C. Complete reversal by protamine

    Protamine reverses only about 60 percent of the anti-Xa effect.

  • D. Direct thrombin inhibition

    Direct thrombin inhibitors are drugs such as argatroban and dabigatran.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is A, Predominant anti-Xa activity with predictable weight-based dosing and no routine aPTT monitoring. Low molecular weight heparins are too short to bridge antithrombin to thrombin, so they act chiefly on factor Xa and have a predictable dose response with better bioavailability.

Why is "Predominant antithrombin activity requiring aPTT monitoring" not the answer?

That describes unfractionated heparin.

Why is "Complete reversal by protamine" not the answer?

Protamine reverses only about 60 percent of the anti-Xa effect.

Why is "Direct thrombin inhibition" not the answer?

Direct thrombin inhibitors are drugs such as argatroban and dabigatran.

What concept does this question test?

It tests Anticoagulants: low molecular weight heparin in Pharmacology. Anti-Xa levels are checked only in special groups such as renal failure or pregnancy.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Anticoagulants: low molecular weight heparin?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.