Cardiovascular System Drugs Flashcards

Loop diuretics such as furosemide act on which segment of the nephron?

Answer: Thick ascending limb of the Loop of Henle

Furosemide inhibits the Na-K-2Cl cotransporter (NKCC2) in the thick ascending limb of the Loop of Henle, producing potent diuresis.

Which statin is considered most potent and is also a substrate of OATP1B1, making it susceptible to drug interactions with cyclosporine?

Answer: Rosuvastatin

Rosuvastatin is among the most potent statins and is transported into hepatocytes by OATP1B1; cyclosporine inhibits this transporter, raising rosuvastatin plasma levels.

Digoxin toxicity is potentiated by hypokalemia because:

Answer: Potassium and digoxin compete for the same binding site on Na/K-ATPase

Potassium and digoxin compete for the same binding site on the Na/K-ATPase; low potassium means less competition and enhanced digoxin binding and toxicity.

Sacubitril/valsartan (Entresto) improves heart failure outcomes by combining an ARB with an inhibitor of which enzyme?

Answer: Neprilysin

Sacubitril inhibits neprilysin, which normally breaks down natriuretic peptides; blocking it raises BNP/ANP levels, promoting vasodilation and natriuresis.

Which antiarrhythmic is the first-line IV agent for terminating paroxysmal supraventricular tachycardia (PSVT) due to AV nodal re-entry?

Answer: Adenosine

Adenosine transiently blocks AV nodal conduction by activating A1 receptors, interrupting re-entrant circuits that sustain PSVT.

Thiazide diuretics are contraindicated in which electrolyte imbalance because they worsen it?

Answer: Hypercalcemia

Thiazides reduce urinary calcium excretion by enhancing distal tubule calcium reabsorption, making hypercalcemia worse.

Ivabradine reduces heart rate by blocking which ion channel in sinoatrial node pacemaker cells?

Answer: Funny current (If) channels (HCN channels)

Ivabradine selectively inhibits the hyperpolarization-activated funny current (If) in the SA node, slowing spontaneous depolarization and heart rate.