DO Pharmacology and Therapeutics 1 — Questions and Answers
Question 1: Which class of medications is first-line for managing hypertension in a patient with concurrent type 2 diabetes and proteinuria?
- ACE inhibitors or ARBs (Correct answer)
- Beta-blockers
- Calcium channel blockers
- Thiazide diuretics
Correct answer: ACE inhibitors or ARBs
ACE inhibitors and ARBs are first-line in diabetic patients with proteinuria because they reduce intraglomerular pressure and slow nephropathy progression.
Question 2: A patient taking warfarin is started on rifampin. How should warfarin dosing be adjusted?
- Increase warfarin dose; rifampin induces CYP450 enzymes (Correct answer)
- Decrease warfarin dose; rifampin inhibits CYP450 enzymes
- No adjustment needed
- Switch to heparin immediately
Correct answer: Increase warfarin dose; rifampin induces CYP450 enzymes
Rifampin is a potent CYP450 inducer that accelerates warfarin metabolism, reducing its anticoagulant effect and requiring a higher dose.
Question 3: Which antibiotic class is associated with QT prolongation and must be used cautiously in patients on antiarrhythmics?
- Fluoroquinolones (Correct answer)
- Penicillins
- Aminoglycosides
- Carbapenems
Correct answer: Fluoroquinolones
Fluoroquinolones (e.g., ciprofloxacin, levofloxacin) can prolong the QT interval, increasing the risk of torsades de pointes especially with other QT-prolonging drugs.
Question 4: Metformin is contraindicated in patients with an eGFR below what threshold due to risk of lactic acidosis?
- 30 mL/min/1.73m² (Correct answer)
- 60 mL/min/1.73m²
- 45 mL/min/1.73m²
- 15 mL/min/1.73m²
Correct answer: 30 mL/min/1.73m²
Metformin should be discontinued when eGFR falls below 30 mL/min/1.73m² because reduced renal clearance allows metformin accumulation and lactic acid buildup.
Question 5: Which opioid analgesic is safest to use in patients with chronic kidney disease because it lacks active renally cleared metabolites?
- Fentanyl (Correct answer)
- Morphine
- Codeine
- Hydromorphone
Correct answer: Fentanyl
Fentanyl is metabolized to inactive compounds and does not accumulate in renal failure, making it safer than morphine whose active metabolite (M6G) can cause toxicity.
Question 6: Statins exert their primary lipid-lowering effect by inhibiting which enzyme?
- HMG-CoA reductase (Correct answer)
- Lipoprotein lipase
- Cholesterol ester transfer protein
- Lecithin-cholesterol acyltransferase
Correct answer: HMG-CoA reductase
Statins competitively inhibit HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis, reducing LDL-C levels.
DO Pharmacology and Therapeutics 1
Which class of medications is first-line for managing hypertension in a patient with concurrent type 2 diabetes and proteinuria?