Source / episode info
- **Episode:**380
- **Title:**Divine Intervention Episode 380 – USMLE Step 2CK/3 Rapid Review Series 72
- **Published:**2022-03-18
- Source:Episode page
One-liner
This episode provides a high-yield review of complex pharmacology concepts, emphasizing the precise nomenclature and mechanism of enzyme inhibitors (DNA/RNA polymerase), differentiating antibiotic classes based on Gram stain coverage, and linking drug side effects like hyperkalemia ({TMP-SMX}) or hemolysis (G6PD deficiency) to underlying physiological pathways.
High-yield summary
- Herpes Management: Herpes zoster/herpetic whitlow is treated with oral Acyclovir. IV administration is reserved only for severe illness, immunocompromise, or inability to tolerate oral intake.
- Enzyme Inhibitor Nomenclature: Test your ability to classify inhibitors by their template and product (e.g., {NRTIs} are inhibitors of an RNA-dependent DNA polymerase; Rifampin inhibits RNA polymerase).
- Aminoglycosides vs. Vancomycin: Use Gram stain/site of infection as the primary differentiator: Aminoglycosides for suspected Gram-negative infections (e.g., kidney infection); Vancomycin for suspected Gram-positive infections.
- Antifolate Toxicity ({TMP-SMX}): {Trimethoprim-Sulfamethoxazole} causes hyperkalemia by inhibiting dihydrofolate reductase and dihydroetherease synthetase, leading to the suppression of {ENaC} channels in the principal cells.
- G6PD Deficiency: This X-linked recessive disorder predisposes males (especially African American or Mediterranean descent) to acute hemolytic anemia when exposed to powerful oxidizing agents (e.g., nitrofurantoin, sulfa drugs, nitrates).
Learning objectives
- Differentiate between oral vs. IV administration protocols for viral infections (e.g., Herpes).
- Classify enzyme inhibitors based on their template dependence (\text{DNA} -> \text{RNA}, \text{RNA} -> \text{DNA}, etc.).
- Apply knowledge of antibiotic spectrum to select appropriate agents based on suspected pathogen Gram stain.
- Explain the mechanism by which antifolates cause hyperkalemia via disruption of principal cell ion transport.
- Recognize the clinical presentation and triggers for Glucose-6-Phosphate Dehydrogenase deficiency.
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