Pharmacology Antimicrobial Therapy Principles 3

Question 1

A patient with a creatinine clearance of 15 mL/min requires antibiotic therapy. Which agent requires the most significant dose reduction?

Accepted Answer

Vancomycin

Answer

Vancomycin is primarily renally eliminated and requires substantial dose adjustment (extended intervals or reduced doses) in severe renal impairment.

Question 2

Bacteriostatic antibiotics are generally preferred over bactericidal agents in which clinical scenario?

Accepted Answer

Mild community-acquired pneumonia in an immunocompetent host

Answer

In immunocompetent patients with mild infections, bacteriostatic antibiotics are sufficient because the host immune system can clear growth-inhibited bacteria.

Question 3

Which antibiotic is considered the drug of choice for treating Legionella pneumophila pneumonia?

Accepted Answer

Azithromycin

Answer

Azithromycin (or other macrolides/fluoroquinolones) is first-line for Legionella because the organism is an intracellular pathogen and beta-lactams have no efficacy.

Question 4

Combining a beta-lactam with a beta-lactamase inhibitor (e.g., amoxicillin-clavulanate) expands coverage primarily against which organisms?

Accepted Answer

Beta-lactamase-producing Haemophilus influenzae and anaerobes

Answer

Beta-lactamase inhibitors protect the beta-lactam from hydrolysis, restoring activity against organisms that produce beta-lactamase enzymes.

Question 5

A patient is treated with trimethoprim-sulfamethoxazole (TMP-SMX). Which nutrient synthesis pathway does this combination block?

Accepted Answer

Folate synthesis

Answer

TMP inhibits dihydrofolate reductase and SMX inhibits dihydropteroate synthase, together blocking sequential steps in folate synthesis.

Pharmacology Practice Test

Pharmacology Practice Test

Pharmacology Antimicrobial Therapy Principles 3