CMC CMC Cardiac Pharmacology & Medications 2 — Questions and Answers
Question 1: Loop diuretics like furosemide reduce fluid overload by inhibiting which transporter in the kidney?
- Na+/K+/2Cl- cotransporter in the loop of Henle (Correct answer)
- Sodium-hydrogen exchanger in the proximal tubule
- Aquaporin channels in the collecting duct
- ENaC channels in the distal tubule
Correct answer: Na+/K+/2Cl- cotransporter in the loop of Henle
Furosemide blocks the Na+/K+/2Cl- cotransporter in the thick ascending limb of the loop of Henle, promoting diuresis.
Question 2: Amiodarone is classified as which type of antiarrhythmic drug based on the Vaughan-Williams classification?
- Class I
- Class II
- Class III (Correct answer)
- Class IV
Correct answer: Class III
Amiodarone is a Class III antiarrhythmic that primarily blocks potassium channels, prolonging the cardiac action potential.
Question 3: Which antiarrhythmic drug can cause thyroid dysfunction as a significant long-term side effect?
- Lidocaine
- Metoprolol
- Amiodarone (Correct answer)
- Verapamil
Correct answer: Amiodarone
Amiodarone contains approximately 37% iodine by weight and can cause both hypothyroidism and hyperthyroidism.
Question 4: Spironolactone, an aldosterone antagonist, is most beneficial in which cardiac condition?
- Paroxysmal atrial fibrillation
- Heart failure with reduced ejection fraction (Correct answer)
- Hypertensive crisis
- Wolff-Parkinson-White syndrome
Correct answer: Heart failure with reduced ejection fraction
Spironolactone reduces mortality in HFrEF by blocking aldosterone-mediated cardiac fibrosis and sodium retention.
Question 5: Aspirin reduces platelet aggregation and cardiovascular events through which mechanism?
- Reversible COX-2 inhibition
- Irreversible COX-1 inhibition reducing thromboxane A2 (Correct answer)
- Direct thrombin inhibition
- Plasminogen activation
Correct answer: Irreversible COX-1 inhibition reducing thromboxane A2
Aspirin irreversibly acetylates COX-1, permanently preventing thromboxane A2 synthesis for the platelet's lifetime.
Question 6: Non-dihydropyridine calcium channel blockers are contraindicated in which cardiac condition?
- Stable angina
- Hypertension
- Decompensated heart failure (Correct answer)
- Atrial flutter
Correct answer: Decompensated heart failure
Non-dihydropyridine CCBs reduce myocardial contractility and can precipitate cardiogenic shock in decompensated heart failure.
CMC CMC Cardiac Pharmacology & Medications 2
Loop diuretics like furosemide reduce fluid overload by inhibiting which transporter in the kidney?