Gce Model Questions Vol1 2023 Biology Question 5

Practice objective / multiple choice question 5 from the 2023 Gce Model Questions Vol1 Biology examination.

Gce Model Questions Vol1 2023 Biology Objective / Multiple Choice Hard Difficulty
Question 5 GCE_MODEL_QUESTIONS_VOL1 • 2023 • BIOLOGY • objective

A drug follows first‑order elimination with a half‑life of 6 h. It is given orally every 8 h at a dose \(D\) mg, bioavailability \(F=0.8\), and apparent volume of distribution \(V_{d}=40\) L. At steady state the peak concentration after a dose is 15 µg mL⁻¹ and the trough just before the next dose is 5 µg mL⁻¹.\n\n(a) Determine the dose \(D\) (mg) required to produce these concentrations.\n(b) If the dosing interval is changed to 12 h while keeping the same dose per administration, will the peak and trough concentrations remain within the therapeutic window of 8-12 µg mL⁻¹? Show all calculations.

Answer Options

A. Dose D ≈ 452 mg; the 12‑h regimen fails to stay within the therapeutic window (peak ≈11.0 µg mL⁻¹, trough ≈4.0 µg mL⁻¹).
Correct Answer B. Dose D ≈ 452 mg; the 12‑h regimen fails to stay within the therapeutic window (peak ≈12.05 µg mL⁻¹, trough ≈3.01 µg mL⁻¹).
C. Dose D ≈ 380 mg; the 12‑h regimen stays within the therapeutic window (peak ≈10.2 µg mL⁻¹, trough ≈7.8 µg mL⁻¹).
D. Dose D ≈ 520 mg; the 12‑h regimen fails to stay within the therapeutic window (peak ≈13.5 µg mL⁻¹, trough ≈2.5 µg mL⁻¹).
Correct Answer
B
Correct Option:
Dose D ≈ 452 mg; the 12‑h regimen fails to stay within the therapeutic window (peak ≈12.05 µg mL⁻¹, trough ≈3.01 µg mL⁻¹).

About This Question

This is Gce Model Questions Vol1 2023 Biology Question 5. It is one of the objective questions from the 2023 Gce Model Questions Vol1 Biology examination.

Difficulty level: Hard .

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