Antimicrobial and Chemotherapeutic Agents Flashcards
7 cards from real Pharmacology 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 and Chemotherapeutic Agents flashcards as text
A patient with HIV is started on antiretroviral therapy. Which drug class inhibits HIV integrase, preventing viral DNA from inserting into the host genome?
Answer: Integrase strand transfer inhibitors (INSTIs)
Integrase strand transfer inhibitors (e.g., raltegravir, dolutegravir) block the HIV integrase enzyme, preventing integration of viral cDNA into the host cell nucleus.
Which antibiotic is bacteriostatic and works by binding the 30S ribosomal subunit to inhibit aminoacyl-tRNA binding?
Answer: Tetracycline
Tetracyclines reversibly bind the 30S ribosomal subunit at the A site, blocking aminoacyl-tRNA attachment and thereby halting protein elongation in a bacteriostatic manner.
Caspofungin belongs to which antifungal class, and what is its mechanism of action?
Answer: Echinocandin; inhibits beta-(1,3)-D-glucan synthase
Caspofungin is an echinocandin that inhibits beta-(1,3)-D-glucan synthase, disrupting cell wall synthesis — a mechanism with no human cell wall equivalent, resulting in selective toxicity.
A patient taking rifampin for tuberculosis reports that their oral contraceptives have become less effective. The most likely explanation is:
Answer: Rifampin induces CYP450 enzymes, accelerating contraceptive metabolism
Rifampin is a potent CYP450 inducer that increases hepatic metabolism of estrogens and progestins, significantly reducing plasma levels of oral contraceptives.
Which antibiotic is the treatment of choice for Lyme disease caused by Borrelia burgdorferi in adults?
Answer: Doxycycline
Doxycycline is first-line treatment for early Lyme disease in adults and is also effective against early disseminated Lyme disease without neurologic involvement.
A hospitalized patient develops antibiotic-associated diarrhea after broad-spectrum antibiotic therapy. Stool testing is positive for Clostridioides difficile toxins. Current preferred first-line treatment is:
Answer: Oral fidaxomicin
Current IDSA guidelines recommend fidaxomicin as preferred first-line therapy for C. difficile infection because it has lower recurrence rates than vancomycin.
Which antiretroviral drug class works by competitively blocking HIV from binding to the CCR5 co-receptor on CD4+ T cells?
Answer: CCR5 antagonists
CCR5 antagonists such as maraviroc block the CCR5 co-receptor, preventing R5-tropic HIV strains from attaching to and entering CD4+ T cells.