Cardiovascular/HTN Flashcards
(88 cards)
How prevalent is HTN in the USA?
30% or more (1/3 of Americans have HTN)
What is HTN?
BP 140/90
What causes HTN
idiopathic
CO increases and peripheral vascular resistance increases
Why is HTN bad?
if untreated for a long time can cause:
outcome is
not good for t heart untreated for a long time can cause: ♣ CHF ♣ Aneurysm ♣ Vision issues ♣ Renal failure
poor
A person who is normotensive at age 55 has up to a ___% chance of developing HTN
90
HTN is the #1 reason for
office visits
a decrease in BP of 2mmHg can
lower risk of cardiovascular events by 10%
JNC 8 (JNC - Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure) says that the following types of pts should start pharmacotherapy at what BP?
- Patients <60 years of age
-Pts with diabetes start tx at
with CKD
60+ years old
Patients <60 years of age = 140/90
patients with diabetes= 140/90
Patients with CKD= 140/90
Patients 60 years of age or greater =150/90
why would patients 60+ years of age start tx at a higher BP?
Systolic is high but diastolic is okay this is called isolated systolic HTN and a lot of old people get this (usually like 170/70)
Arteries get stiffer with age so BP goes up
Don’t start tx until later because their BP is normally higher
What do we tx HTN with?
thiazide Diuretics, ACE inhibitors, ARBs, CCBs
How do diuretics work?
Diuretics work by depleting sodium (sodium wasting)
“Where sodium goes, so goes water” (if you get rid of Na+, water will also leave and BP will decrease
Only class of diuretics recommended in HTN
thiazides
as you move through the nephron less and less ____ happens
explain
reabsorption
near the glomerulus 60-70% of absorption occurs there
but as you get down passed the loop of henle it drops down to 25% and then in the distal convoluted tubules it drops to 5%
Loop diuretics—bad because they decrease
tons of fluid
Hydrochlorothiazide (HCTZ) (thiazide diuretic)
- ____ derivative so need to watch out for
- MOA=
-sulfonamide, allergies (people with sulfa allergies)
-decrease reabsorption in distal convoluted tubules
by Blocking Na+-CL- symporter on luminal membrane
**this is where 5% of reabsorption takes place and HCTZ blocks it
HCTZ =hydrochlorotiazide
effects
Na+ and Cl- loss K+ loss Mg2+ loss (mechanism unknown) Decreased Ca2+ excretion Decreased peripheral vascular resistance (mechanism unknown)
• HCTZ =hydrochlorotiazide has to be secreted into lumen so kidney has to be
functioning and working very well. So that means glomerulus has to be perfused and still be filtering (fluid has to be coming out of the glomerulus)
• How does the glomerulus work
in order for thiazides to work, glomerulus has to be very
They work on hydrostatic pressure so they are like balloons with a bunch of holes in it
o Not a lot of water is going to come out of holes if you have just a little fluid inside deflated balloon
o If you have a lot of fluid (very perfused) lots of fluid can come out of the holes
o So in order for thiazides to work, glomeruli have to be very perfused
can pts kidney dysfxn take hydrochlorothiazide?
no they will not take these drugs –doesn’t work because their kidneys are not perfused
with HCTZ how long does it take to see consistent decrease in BP?
Effective with renal failure?
Takes up to 3 weeks to see consistent decrease in BP (it will take a little while)
• Not effective if you have renal failure (ineffective if GFR is below 30ml/min)
HCTZ is called ceiling drugs—because
if you Increase dose beyond a certain point does not increase diuresis
adverse affects of HCTZ
o adverse affects ♣ hypokalemia ♣ hyponatremia ♣ hyperuricemia—gout ♣ hypercalcemia ♣ hyperglycemia if pt has high blood sugar, or is diabetic, this drug could push them up so diabetic can use it, but you need to monitor their blood sugar and put them on some other drug to help blood sugar ♣ volume depletion
Drugs that are just like Thiazides (“Thiazide-like” Diuretics)
name 3
which do we prefer, these or HCTZ?
chlorthalidone
indapeamide (lozol)
Matolazone (Zaroxolyn)
We prefer to use the first 2 (chlorothalidone and indapeamide) over hydrochlorothiazide
we use to use HCTZ a lot but now we are seeing more chlorthalidone and indapamide
Drug Interactions with Thiazide-Like Diuretics
1) Uricosuric agents (namely, probenecid) → compete for secretion into proximal tubule and thiazides interfere with uric acid excretion
2) Sulfonylureas and insulin → decreased effectiveness in maintaining blood sugar
3) **Quinidine → increased risk of QT prolongation; potentially fatal
4) Drugs that potentiate orthostatic hypotension
5) Hypokalemia may increase digitalis toxicity
6) NSAIDs
7) Beta-blockers → hyperglycemia/hyperlipidemia
8) Corticosteroids → hypokalemia
