General pharmacology: high first-pass metabolism: 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.

Try it

Pharmacology · General pharmacology: high first-pass metabolism

Sample item

A patient with ventricular arrhythmia is considered for lidocaine. Why is lidocaine given parenterally rather than orally?

AIt causes severe gastric irritationBIt is destroyed by gastric acidCIt is not absorbed because it is highly ionisedDExtensive first-pass hepatic metabolism leaves very little active drug after oral dosing

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

The answer and the reasoning

D. Extensive first-pass hepatic metabolism leaves very little active drug after oral dosing

Lidocaine has a high hepatic extraction ratio, so most of an oral dose is metabolised before reaching the systemic circulation. Drugs with high first-pass effect need much higher oral doses or a route that bypasses the liver.

Option by option

A. It causes severe gastric irritation
Gastric irritation is not the limiting feature of lidocaine.
B. It is destroyed by gastric acid
Lidocaine is not acid labile; the problem is hepatic metabolism.
C. It is not absorbed because it is highly ionised
Poor absorption is not the main reason; the liver removes it after absorption.
D. Extensive first-pass hepatic metabolism leaves very little active drug after oral dosing (correct)
Correct. High first-pass extraction makes oral bioavailability very low.

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.

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Extensive first-pass hepatic metabolism leaves very little active drug after oral dosing. Lidocaine has a high hepatic extraction ratio, so most of an oral dose is metabolised before reaching the systemic circulation.

Why is "It causes severe gastric irritation" not the answer?

Gastric irritation is not the limiting feature of lidocaine.

Why is "It is destroyed by gastric acid" not the answer?

Lidocaine is not acid labile; the problem is hepatic metabolism.

Why is "It is not absorbed because it is highly ionised" not the answer?

Poor absorption is not the main reason; the liver removes it after absorption.

What concept does this question test?

It tests General pharmacology: high first-pass metabolism in Pharmacology. Drugs with high first-pass effect need much higher oral doses or a route that bypasses the liver.

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 General pharmacology: high first-pass metabolism?

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.