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Antimicrobial Pharmacology Flashcards

7 cards from real MCCQE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Antimicrobial Pharmacology flashcards as text

  1. A patient with MRSA bacteremia is started on vancomycin. Therapeutic drug monitoring is performed. Which pharmacokinetic/pharmacodynamic parameter best predicts vancomycin efficacy against MRSA?

    Answer: AUC24/MIC ratio of 400-600

    Current guidelines recommend targeting an AUC24/MIC ratio of 400-600 mg·h/L as the best PK/PD predictor of vancomycin efficacy for serious MRSA infections.

  2. Chloramphenicol causes which unique, dose-independent, potentially fatal hematologic adverse effect?

    Answer: Aplastic anemia via idiosyncratic bone marrow suppression

    Chloramphenicol can cause rare but fatal idiosyncratic aplastic anemia unrelated to dose, distinct from its reversible, dose-dependent bone marrow suppression.

  3. A patient with a sulfonamide allergy requires prophylaxis for Pneumocystis jirovecii pneumonia. Which alternative is most appropriate?

    Answer: Atovaquone

    Atovaquone is a preferred TMP-SMX alternative for PCP prophylaxis in patients with sulfonamide allergy who cannot use dapsone due to its own adverse effects or G6PD deficiency.

  4. Which mechanism explains why beta-lactam antibiotics are most effective against rapidly dividing bacteria?

    Answer: Cell wall synthesis only occurs during active bacterial growth, requiring PBP activity

    Beta-lactams inhibit transpeptidation of peptidoglycan, a process that only occurs during active cell wall synthesis in growing bacteria.

  5. A traveler returns from Southeast Asia with severe malaria caused by Plasmodium falciparum. Chloroquine resistance is suspected. Which combination treatment is standard first-line therapy?

    Answer: Artemisinin-based combination therapy (ACT)

    Artemisinin-based combination therapy (ACT) is the WHO-recommended first-line treatment for uncomplicated chloroquine-resistant P. falciparum malaria.

  6. Rifampin is a potent inducer of CYP3A4. Which clinical consequence is most important when co-administering rifampin with oral contraceptives?

    Answer: Contraceptive failure due to accelerated estrogen and progestin metabolism

    Rifampin induces CYP3A4 and accelerates metabolism of estrogen and progestin, reducing oral contraceptive plasma levels and causing contraceptive failure.

  7. Which antiviral agent used for influenza inhibits viral neuraminidase and should be given within 48 hours of symptom onset for maximum benefit?

    Answer: Oseltamivir

    Oseltamivir inhibits influenza neuraminidase, preventing viral release from infected cells, and is most effective when initiated within 48 hours of symptom onset.