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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 Type 1 diabetes presents with a diabetic foot infection. Wound culture grows Pseudomonas aeruginosa. Which antibiotic has reliable anti-pseudomonal activity?

    Answer: Piperacillin-tazobactam

    Piperacillin-tazobactam has reliable anti-pseudomonal activity because piperacillin's ureidopenicillin structure allows it to penetrate Pseudomonas's outer membrane.

  2. Which antifungal mechanism of action is shared by both fluconazole and voriconazole?

    Answer: Inhibition of lanosterol 14α-demethylase (CYP51)

    Both fluconazole and voriconazole are azoles that inhibit fungal CYP51 (lanosterol 14α-demethylase), blocking ergosterol biosynthesis.

  3. A patient with renal failure is prescribed imipenem-cilastatin. Why is cilastatin included in this formulation?

    Answer: It inhibits renal dehydropeptidase-I, preventing imipenem hydrolysis in the kidney

    Cilastatin inhibits dehydropeptidase-I on the renal brush border, preventing hydrolysis of imipenem to a nephrotoxic metabolite and increasing urinary drug levels.

  4. Gray baby syndrome associated with chloramphenicol in neonates is caused by which mechanism?

    Answer: Immature hepatic UDP-glucuronosyltransferase causes toxic drug accumulation

    Neonates have immature hepatic glucuronidation (UDP-glucuronosyltransferase), causing chloramphenicol to accumulate to toxic levels, resulting in cardiovascular collapse.

  5. A patient on isoniazid (INH) for latent TB prophylaxis develops peripheral neuropathy. Which supplement should be co-administered with INH to prevent this complication?

    Answer: Vitamin B6 (pyridoxine)

    INH competitively inhibits pyridoxal phosphate (active vitamin B6) metabolism, causing deficiency that leads to peripheral neuropathy; pyridoxine supplementation prevents this.

  6. Which mechanism explains the synergy between penicillin and an aminoglycoside in treating Enterococcus faecalis endocarditis?

    Answer: Penicillin disrupts cell wall integrity, enhancing aminoglycoside entry into the bacterial cell

    Penicillin disrupts the enterococcal cell wall, enabling greater aminoglycoside uptake, which overcomes intrinsic low-level aminoglycoside resistance in Enterococcus.

  7. A patient receiving amphotericin B develops rigors, fever, and hypokalemia. Which intervention reduces infusion-related reactions to amphotericin B?

    Answer: Pre-treating with IV corticosteroids and slowing the infusion rate

    Pre-medicating with acetaminophen, diphenhydramine, and corticosteroids combined with slower infusion rates significantly reduces amphotericin B infusion-related reactions.