General Pharmacology MCQs

Pharmacology · 5 free questions with answers & explanations.

1. A drug has a volume of distribution (Vd) of 700 L in a 70 kg patient. Which statement best explains this finding?
2. A drug is administered intravenously with a half-life of 8 hours. Approximately how long will it take to reach steady-state plasma concentration with a fixed-interval dosing regimen?
3. A 70-year-old woman requires a drug that undergoes extensive first-pass metabolism in the liver. Compared to a 30-year-old adult at the same oral dose, which pharmacokinetic change is MOST likely in the elderly patient?
4. Drug X has an EC50 of 5 ng/mL, while Drug Y (same class, same receptor) has an EC50 of 50 ng/mL. Both achieve the same maximum effect. Which statement is correct?
5. A patient on phenytoin for epilepsy is started on rifampicin for tuberculosis. Two weeks later, his seizure frequency increases despite good adherence. What is the most likely pharmacokinetic explanation?