Lecture 10: CV Part 1 Flashcards
Where does angiotensinogen come from?
Liver
Where does renin come from?
Kidneys
What converts angiotensinogen to angiotensin 1?
Renin
What convert angiotensin 1 to angiotensin 2?
ACE from kidneys and lungs.
Angiotensin converting enzyme
What does angiotensin II do?
Increased sympathetic activity
Na+ Cl- absorption, K+ excretion, H2O retention
Increased aldosterone secretion
Arteriolar vasoconstriction
ADH secretion
What can cause increased angiotensinogen production?
Corticosteroids, estrogens, thyroid hormones, pregnancy.
Is ANG 1 as potent as ANG II?
No. ANG 1 has little to no biologic effect.
What are the two AT receptors and their effects?
AT1:
Vasoconstriction
Sympathetic activation
Cell growth
Sodium/fluid retention.
AT2:
Vasodilation
Inhibition of Cell growth
Embryonal development
Apoptosis
What drugs can inhibit the RAAS?
Renin inhibitors
ACE inhibitors
ARBs
Aldosterone antagonists
What do ACEI do in RAAS?
Block ACE, which prevents the conversion of ANG 1 to ANG 2. Also prevents breakdown of bradykinin, which causes extra vasodilation.
What do all ACE inhibitors end in?
pril!
Common:
BenazePRIL
CaptoPRIL
EnalaPRIL
LisinoPRIL
RamiPRIL
What are the PK considerations for an ACE inhibitor?
Hepatic conversion to active metabolite. Exceptions are captopril and lisinopril.
Kidney elimination. Exception is fosinopril.
Enalaprilat is the only IV ACE inhibitor. All others are oral.
What 3 things do we use ACE inhibitors for?
First line antiHTN.
Cardioprotective (patients with systolic HF and pts with HTN and at risk for CAD)
Renal protective (slow diabetic nephropathy)
What does an ACE inhibitor do to arterioles in the kidney?
It dilates the efferent arteriole, dropping intraglomerular pressure and reducing filtration.
Note: Normally, AT2 constricts efferent arterioles much more than afferent.
What are the common symptoms of an ACE inhibitor?
Dry, hacking cough (5-20%, not dose-related, due to bradykinin)
Hypotension
Hyperkalemia (reduces aldosterone, which excretes K+)
What are the adverse effects of an ACE inhibitor?
Angioedema (usually occurs within 1 week)
Acute Renal Failure
What are the contraindications of an ACE inhibitor?
Pregnancy (Category D)
Hypersensitivity to ACE inhibitors
Hx of angioedema
Coadministration with renin inhibitor in patient with DM or renal impairment.
BILATERALrenal artery stenosis
What do ACE inhibitors interact with?
Potassium supplements, potassium-sparing diuretics, mineralcorticoid receptor antagonists, or ARBs, all of which can cause hyperkalemia.
NSAIDs.
What are some clinical pearls regarding ACE inhibitors?
Adequate BP control as monotherapy. (start low and go slow)
One is usually not better than the other.
Intermediate durations of actions, QD dosing.
(Exception is captopril, TID/ER required)
Monitor potassium and serum creatinine levels.
Warn patients about cough and angioedema.
What does ARB stand for?
Angiotensin receptor blocker.