Pharmacy Clinical Pharmacy 4 — Questions and Answers
Question 1: A patient with community-acquired pneumonia (CAP) and penicillin allergy (anaphylaxis) requires antibiotic therapy. Which agent is most appropriate?
- Amoxicillin-clavulanate
- Ceftriaxone
- Azithromycin monotherapy for outpatient mild CAP (Correct answer)
- Piperacillin-tazobactam
Correct answer: Azithromycin monotherapy for outpatient mild CAP
For mild outpatient CAP with true penicillin anaphylaxis, azithromycin monotherapy is guideline-recommended and avoids cross-reactivity risk.
Question 2: What is the primary advantage of using pharmacokinetic/pharmacodynamic (PK/PD) modeling in antibiotic dosing?
- It eliminates the need for drug level monitoring
- It optimizes dosing to maximize efficacy while minimizing toxicity and resistance (Correct answer)
- It standardizes doses across all patient populations without adjustment
- It replaces culture and sensitivity testing
Correct answer: It optimizes dosing to maximize efficacy while minimizing toxicity and resistance
PK/PD modeling links drug exposure to microbiological outcomes, allowing individualized dosing that maximizes target attainment while limiting toxicity and resistance selection.
Question 3: Which mechanism explains the nephrotoxicity of amphotericin B deoxycholate?
- Blockade of tubular secretion transporters OAT1/OAT3
- Direct binding to renal tubular cell ergosterol causing cytotoxicity and vasoconstriction (Correct answer)
- Immune-complex deposition in glomeruli
- Inhibition of prostaglandin synthesis reducing renal perfusion
Correct answer: Direct binding to renal tubular cell ergosterol causing cytotoxicity and vasoconstriction
Amphotericin B binds ergosterol-like sterols in renal tubular cells and induces afferent arteriolar vasoconstriction, causing direct nephrotoxicity.
Question 4: A 55-year-old patient on warfarin starts taking St. John's Wort. What pharmacokinetic outcome is expected?
- Increased warfarin levels due to inhibition of P-glycoprotein
- Decreased warfarin levels due to CYP3A4 induction (Correct answer)
- No significant interaction with warfarin
- Increased warfarin levels due to protein-binding displacement
Correct answer: Decreased warfarin levels due to CYP3A4 induction
St. John's Wort is a potent inducer of CYP3A4 and P-glycoprotein, accelerating warfarin metabolism and reducing anticoagulation.
Question 5: When counseling a patient on albuterol inhaler technique, which step is most critical for effective drug delivery to the lower airways?
- Exhaling forcefully immediately after actuation
- Inhaling slowly and deeply while actuating the inhaler (Correct answer)
- Shaking the inhaler only before the first use
- Holding the inhaler upside down during inhalation
Correct answer: Inhaling slowly and deeply while actuating the inhaler
A slow, deep inhalation coordinates with actuation to maximize deposition of drug particles in the lower airways rather than the oropharynx.
Question 6: A patient newly diagnosed with type 2 diabetes has an HbA1c of 9.2%. Per ADA guidelines, what is the initial pharmacotherapy recommendation?
- Lifestyle modification alone for 3 months
- Metformin monotherapy only
- Metformin plus a second agent or insulin depending on symptoms (Correct answer)
- Insulin therapy exclusively given the high HbA1c
Correct answer: Metformin plus a second agent or insulin depending on symptoms
ADA guidelines recommend dual therapy (metformin + a second agent) or insulin for HbA1c ≥9% to achieve glycemic targets more rapidly.
Question 7: Which lab value indicates adequate anticoagulation with unfractionated heparin (UFH) in venous thromboembolism treatment?
- INR of 2.0–3.0
- Anti-Xa level of 0.3–0.7 IU/mL
- aPTT 1.5–2.5 times the control value (Correct answer)
- Platelet count above 150,000/μL
Correct answer: aPTT 1.5–2.5 times the control value
UFH therapeutic effect is monitored by aPTT targeted at 1.5–2.5 times the institutional control value, corresponding to anti-Xa levels of 0.3–0.7 IU/mL.
Pharmacy Clinical Pharmacy 4
A patient with community-acquired pneumonia (CAP) and penicillin allergy (anaphylaxis) requires antibiotic therapy.
Which agent is most appropriate?