Pharmacology Antimicrobial Therapy Principles 5

Question 1

A febrile neutropenic patient with no identified source of infection requires empiric antibiotic therapy. Which regimen is most appropriate?

Accepted Answer

Anti-pseudomonal beta-lactam (e.g., piperacillin-tazobactam)

Answer

Febrile neutropenia requires empiric antipseudomonal beta-lactam therapy (piperacillin-tazobactam, cefepime, or meropenem) to cover gram-negative pathogens including Pseudomonas.

Question 2

Which antimicrobial property describes the ability of a drug to reach effective concentrations at the site of infection?

Accepted Answer

Tissue penetration

Answer

Tissue penetration describes how well an antibiotic reaches the site of infection, which is critical for treating infections in poorly perfused sites like bone or abscesses.

Question 3

Resistance via outer membrane porin loss primarily affects which class of antibiotics and in which organism?

Accepted Answer

Carbapenems in Pseudomonas aeruginosa (OprD loss)

Answer

Loss of the OprD outer membrane porin in Pseudomonas aeruginosa reduces uptake of imipenem, conferring resistance to carbapenems.

Question 4

A patient taking rifampin for tuberculosis is started on oral contraceptives. What counseling is most important?

Accepted Answer

Rifampin induces CYP450 enzymes, reducing oral contraceptive effectiveness

Answer

Rifampin is a potent CYP450 inducer that accelerates estrogen and progestin metabolism, significantly reducing oral contraceptive plasma levels and efficacy.

Question 5

Which condition is most likely to require surgical source control in addition to antibiotic therapy?

Accepted Answer

Liver abscess

Answer

Liver abscesses often require drainage (percutaneous or surgical) in addition to antibiotics because antibiotics alone penetrate poorly into the necrotic abscess core.

Pharmacology Practice Test

Pharmacology Practice Test

Pharmacology Antimicrobial Therapy Principles 5