NR 567 Advanced Pharmacology Exam with Questions and Answers

NR 567 Advanced Pharmacology Exam with Questions and Answers A 62-year-old man with chronic kidney disease (stage IV) is prescribed a renally excreted antibiotic. His creatinine clearance is significantly reduced, and steady-state drug levels are being evaluated. The physician considers adjusting the dosing regimen based on pharmacokinetic principles. Which pharmacokinetic parameter is most directly affected by his renal impairment? a. Volume of distribution b. Bioavailability c. Absorption rate constant d. Clearance Correct Answer : D Rationale : Renal impairment primarily reduces drug clearance, especially for drugs eliminated unchanged via the kidneys. Clearance determines how efficiently the drug is removed from the body and directly influences steady-state concentration. Volume of distribution and absorption are less affected in this scenario, while bioavailability is unrelated to renal excretion. A 45-year-old woman with epilepsy is started on a drug with nonlinear (Michaelis-Menten) pharmacokinetics. After a small increase in dose, she develops signs of toxicity. The clinician suspects saturation of metabolic pathways. Which parameter explains this disproportionate increase in plasma concentration? a. First-order elimination constant b. Maximum velocity (Vmax) c. Michaelis constant (Km) d. Half-life Correct Answer : C