In first-order kinetics, which statement correctly describes the relationship among t1/2, Vd, and CL?

Unlock all questions

This demo includes only 20 questions. Upgrade to access hundreds of questions, flashcards, exam simulations, and disable ads.

Full question bankExam simulationsFlashcards
From $24.99Unlock all

Prepare thoroughly for the MDC Pharmacokinetics Exam with our detailed guidance. Utilize flashcards and multiple-choice questions, complete with hints and explanations, to excel in your test!

Multiple Choice

In first-order kinetics, which statement correctly describes the relationship among t1/2, Vd, and CL?

Explanation:
In first-order kinetics, half-life depends on how far a drug distributes in the body relative to how quickly it’s cleared. The relationship is t1/2 = 0.693 × Vd / CL. This means half-life grows with a larger volume of distribution (the drug is more spread out in tissues) and shrinks with a higher clearance (the drug is removed faster). So t1/2 is proportional to Vd and inversely proportional to CL. That’s why the correct statement says t1/2 increases with Vd and decreases with CL. If Vd doubles while CL stays the same, half-life doubles; if CL doubles with Vd constant, half-life halves. The other descriptions conflict with the formula: half-life would not rise with clearance, nor would it be independent of Vd and CL, and a dependence on both in the opposite directions would be incorrect.

In first-order kinetics, half-life depends on how far a drug distributes in the body relative to how quickly it’s cleared. The relationship is t1/2 = 0.693 × Vd / CL. This means half-life grows with a larger volume of distribution (the drug is more spread out in tissues) and shrinks with a higher clearance (the drug is removed faster). So t1/2 is proportional to Vd and inversely proportional to CL.

That’s why the correct statement says t1/2 increases with Vd and decreases with CL. If Vd doubles while CL stays the same, half-life doubles; if CL doubles with Vd constant, half-life halves. The other descriptions conflict with the formula: half-life would not rise with clearance, nor would it be independent of Vd and CL, and a dependence on both in the opposite directions would be incorrect.

More Multiple Choice Questions
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy