Drugs for Cardiac - act on RAAS

Question 1

drugs that act on RAAS

Answer 1

ACEI - angiotensin converting enzyme inhibitors
ARBs - angiotensin II receptor blockers
Aldosterone receptor blockers
Direct Renin inhibitors

Question 2

Angiotensin II in the kidneys

Answer 2

• potent vasoconstrictor = arterioles and veins
• angiotensin I is activated by ACE to become angiotensin II
• ACE inhibitors prevent angiotensin II from activating

Question 3

ACEI (ACE inhibitors) - MOA and indications

Answer 3

MOA

• suppress formation of ANGIOTENSIN II by inhibiting ACE
• ⇡ Bradykinin (inflammatory mediators) -> vasodilation, capillary permeability and cough

Indications:

• treats HTN, HF, MI (prevents another event)
• promote venous dilation, so provide therapeutic effect of reducing pulmonary congestion and peripheral edema.

Question 4

ACEI - which drugs

Answer 4

• pril

Captopril (Capoten)
Enalpril (Vasotec)
Fosinopril (Monopril)
Lisinopril (Zestril)
Ramipril (Altace)

Question 5

bradykinin

Answer 5

a powerful vasodilator that:

• increases capillary permeability
• constricts smooth muscle
• stimulates pain receptors

increased levels = vasodilation, cough, angioedema

Question 6

ACE inhibitors: SE

Answer 6

• “first dose hypotension” - due to widespread vasodilation => start w/low dose
• cough - b/c of build up of bradykinin (most common reason for D/C)
• hyperkalemia
• birth defects
• angioedema (can be fatal)
  = ⇡ capillary permeability => wheals, edema of tongue, pharynx (b/c of ⇡ bradykinin)

Question 7

ACE inhibitors: NIs and Pt education

Answer 7

1. drug-drug interactions
   - ACEI + potassium-sparing diuretics
   - ACEI + salt substitutes
   = need to monitor K+ levels ==> hyperkalemia

Question 8

angiotensin II receptor blockers (ARBs) - which drugs

Answer 8

-sartan

Irbesartan (Avapro)
Losartan (Cozar)
Olmesartan (Benicar)

Question 9

ARBs - MOA

Answer 9

• block angiotensin II actions by inhibiting ACE => dilation of arterioles and veins
  = in adrenals – decr rels of aldosterone => ⇡renal excretion of Na+ and water
• don’t cause cough (like ACEI) => b/c do not cause ⇡ in bradykinin

Question 10

ARBs - side effects

Answer 10

same as ACEI, but don’t cause cough

• lower incidence of hyperkalemia
• angioedema
• decr. HTN

Question 11

Direct Renin Inhibitors (DRI)

Answer 11

newer drug: Aliskiren (Tekturna)

Renin converts angiotensinogen to angiotensin I = by suppressing this step ==> suppresses whole RAAS => decreases BP

Same therapeutic effects as ACEI
BUT, not cough or angioedema

Question 12

Aldosterone Receptor Blockade

Answer 12

retains K+, but ⇡ excretion of Na+ and H20 - similar to a potassium sparing diuretic

eplerenone (selective)
spironolactone (less selective, so more SE)

Question 13

Aldosterone Receptor Blockade - SE

Answer 13

hyperkalemia