Heart failure drugs and their mechanisms

Question 1

Nitroglycerin

Answer 1

Increase NO in smooth muscle –> increase cGMP and smooth muscle relaxation –> vasodilation –> decrease preload and afterload

Question 2

Furosemide (lasix)

Answer 2

Inhibits cotransport system NKCC transporter in thick ascending loop of Henle, stopping reabsorption. Also stimulates PGE release leading to vasodilation

Question 3

Captopril, enalapril, lisinopril, ramipril (ACE inhibitors)

Answer 3

Inhibits conversion of angiotensin I –> Angiotensin II, decreasing aldosterone and decreasing reuptake of Na and water

Question 4

Losartan, candesartan, valsartan (Angiotensin II receptor blockers)

Answer 4

selectively blocks angiotensin II receptors (similar effect as ACE)

Question 5

Metoprolol, propanolol (Beta blockers)

Answer 5

Block Beta 1 receptors and their sympathetic activity on heart rate (decreases SA and AV nodal activity)

Question 6

Spironolactone (K sparing diuretics)

Answer 6

Competitive aldosterone receptor antagonists on collecting tubule

Question 7

Chlorothalidone, hydrochlorothiazide (thiazides)

Answer 7

Inhibits NaCl reabsorption in early distal convoluted tubule

Question 8

Hydralazine

Answer 8

Increase cGMP –> smooth muscle relaxation

Question 9

Ethacrynic acid

Answer 9

Phenoxyacetic acid derivative, essentially same action as furosemide

Question 10

Aspirin (antiplatelet)

Answer 10

Irreversible inhibits COX-1 and COX-2 to inhibit formation of TXA2

Question 11

Morphine (analgesic)

Answer 11

Binds mu opioid receptor to block calcium channels, decreases substance P and glutamate release from 1st order neuron

Question 12

Statins

Answer 12

Inhibits HMG-CoA reductase to inhibit mevalonate (cholesterol precursor)

Question 13

Terazosin (alpha-blocker)

Answer 13

blocks adrenergic receptors (alpha 1 is for SM contraction, Alpha 2 usually releases NE)

Question 14

Verapamil (calcium channel blocker)

Answer 14

Block L-type voltage gated calcium channels to prevent calcium from entering cell (decrease SM contraction). Calcium channel blockers also shift fast-reacting cells that are dependent on Calcium for contraction to sodium for depolarization. This can cause negative inotropic and chronotropic effects.

Question 15

Minodoxil (potassium channel OPENER)

Answer 15

hyperpolarizes cells by allowing potassium to exit cell