3 Heart Failure & Hypertension

Question 1

if cardiac dysfunction is moderate, what is the goal of therapy?

Answer 1

block compensatory response to prevent negative changes in long term

Question 2

4 types of drug therapy to deal with heart failure

Answer 2

• diuretics
• ACE inhibitors/AT1 receptor inhibitors
• b blockers
• vasodilators

Question 3

site of action of diuretics?

Answer 3

thick ascending limb of DCT, DCT and collecting tubule

Question 4

diuretic MOA, effect, use, 2 examples, toxicity

Answer 4

• decrease NaCl reabsorption –> decrease water retention –> increase urination
• decrease blood volume, decrease venous return, decrease BP, decrease pulmonary congestion and peripheral edema
• eg. thiazides - mild CHF
• eg. furosemide - cardiogenic or pulmonary edema
• toxicity - decrease serum K+ –> arrhythmias, muscle weakness

Question 5

2 types of inhibitors of renin-angiotensin system?

Answer 5

• ACE inhibitors

- AT1 antagonist

Question 6

ACE inhibitor MOA, effect, use, 1 example, toxicity

Answer 6

• decrease degradation of bradykinin –> vaodilation
• decrease angiotensin II –> decrease PVR –> decrease NE release –> decrease SNS activity –> decrease aldosterone –> decrease salt/water retention
• effect - decrease blood volume & PVR –> decrease BP –> decrease morbidity and morality in CHF
• given with diuretics/digoxdin
• eg. captopril
• toxicity - severe hypotension, cough, angioedema

Question 7

AT1 antagonist MOA, effect, use, 1 example, toxicity

Answer 7

• AT1 receptor blockade –> vasodilation
• decreases BP, decreases morbidity and mortality in CHF
• for px who can’t tolerate ACE inhibitors
• eg. Losartan
• like ACE inhibitors, but no cough or angioedema

Question 8

b blocker MOA and 1 example

Answer 8

• counter-intuitive, improves cardiac function by decreasing HR and decreasing renin release
• in combo with ACE inhibitors
• eg. metoprolol

Question 9

vasodilator MOA and 1 example

Answer 9

• release NO, increase cGMP, smooth muscle relaxation –> decrease edema and decrease cardiac size
• eg. hydralazine

Question 10

6 drug types to treat hypertension

Answer 10

• same as drugs for heart failure
  – diuretics
  – b blockers
  – ACE inhibitors/AT2 antagonists
  – vasodilators
  PLUS
• calcium channel blockers (vasodilator)
• sympatholytic drugs (vasodilator)

Question 11

calcium channel blocker (vasodilator) MOA, 2 examples, toxicity

Answer 11

• blocks Ca2+ channels in vascular smooth m –> decrease intracellular Ca2+ –> vasodilation
• eg. verapamil, diltiazem
• tox- infrequent hypotension, heart block and cardiac depression (not recommended in HF)

Question 12

sympatholytic drug (eg. clonidine) site of action, MOA, use

Answer 12

• centrally acting
• activates a2 receptors in brain stem –> decrease PVR
• for mild/moderate hypertension that’s unresponsive to diuretics alone
• combined with diuretic to decrease water retention
• less likely to cause postural hypotension

Question 13

sympatholytic drug (eg. prazosin) site of action, MOA, use, toxicity

Answer 13

• peripherally acting
• competitive a1 blockade in vasculature –> decrease PVR
• mild/moderate hypertension with b blocker or diuretic
• tox - reflex tachycardia/dizziness