Pharmacokinetics: 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 · Pharmacokinetics

Sample item

How many half-lives are usually required to approach steady state?

AOne half-life exactlyBAbout four to five half-livesCTwenty half-lives alwaysDHalf-life has no relation

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

The answer and the reasoning

B. About four to five half-lives

With first-order kinetics, most drugs approach practical steady state after roughly four to five half-lives if dose and clearance remain unchanged.

Option by option

A. One half-life exactly
One half-life achieves only partial approach.
B. About four to five half-lives (correct)
Correct: four to five half-lives is the common approximation.
C. Twenty half-lives always
Twenty is not usually necessary.
D. Half-life has no relation
Half-life strongly determines time to steady state.

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 B, About four to five half-lives. With first-order kinetics, most drugs approach practical steady state after roughly four to five half-lives if dose and clearance remain unchanged.

Why is "One half-life exactly" not the answer?

One half-life achieves only partial approach.

Why is "Twenty half-lives always" not the answer?

Twenty is not usually necessary.

Why is "Half-life has no relation" not the answer?

Half-life strongly determines time to steady state.

What concept does this question test?

It tests Pharmacokinetics in Pharmacology. The correct option holds because: Correct: four to five half-lives is the common approximation.

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 Pharmacokinetics?

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.