Cardio- Antihypertensives

Question 1

what are the components of the blood pressure formula (BP)?

Answer 1

CO x PVR

Question 2

what does the term baroreceptors refer to, and where specifically in the cardiovascular system does it apply?

Answer 2

moment to moment regulation of blood pressure.

in carotid artery and aorte- it monitors the stretch of the blood vessles.

Question 3

how do baroreceptors react to an increase in stretch of blood vessels, as well as a contraction of blood vessels?

Answer 3

^ stretch -> baroreceptor stim. -> ˇ in SNS activity.

ˇ stretch -> ˇbaroreceptor activity -> ˆ SNS activity

Question 4

how do kidneys control long-term blood pressure in kidneys* and what hormone is responsible for this mechanism?

Answer 4

when BP ˇ -> ˆ [renin]-> ^[angiotensin 2] -> constricts vessels -> ^ [aldosterone] -> ^Na+ retention and ^ in BLOOD VOLUME*

Question 5

what are the normal levels for BP, as well as the hypertensive, and pre hypertensive?

Answer 5

optimal 115/75
hyper >140/90
pre 120/80

Question 6

hows does Clonidine regulate BP?

Answer 6

CNS adrenergic neurons regulat BP, and there are alpha2 receptors on adrenergic nerver terminals in CNS. Clonidine is an alpha 2 agonist.

Question 7

what is the clonidine mechanism in the body?

Answer 7

clonidine -> ˇ NE in CNS -> ˇ SNS and ˆ PSNS activity = ˇ CO & PVR.

Question 8

what is the toxicity of clonidine?

Answer 8

CNS effects= sedation & impaired concentration

Question 9

What is the effect of Beta Blockers on BP? (both in heat and kidney)

Answer 9

block of beta1 receptors in heart = ˇCO

block of beta1 receptors in juxta-glomerular region of kidney -> ˇ renin release = ˇPVR

Question 10

name a non-selective beta blocker for BP, and name its toxicity.

Answer 10

propranolol,

toxicities associated with beta2 blockade (-asthma)

Question 11

name a selective beta1 blocker.

Answer 11

Metoprolol

Question 12

what are alpha block (in relation to BP), and their toxicity?

Answer 12

a selective alpha1 drug is prazosin. they block alpha 1 receptors in arterioles and venules. salt and water retention occurs, usually pairs with diuretics or beta blockers. and the toxicity is rare : dizziness, palpitations.

Question 13

what are vasodilators, ie. what do they do?

Answer 13

they relax smooth muscles of arterioles, which ˇ PVR & ˇBP, some also relax veins. They work best in combination with other antihypertensives that oppose compensatory responses.

Question 14

name a vasodilator that is a nitric oxide donor.

Answer 14

Sodium nitroprusside
given IV for hypertensive emergencies. 
Its fact acting 
it dilates arterial and venous vessels. 
its toxicitiesL hypotension, cyanide accumulation

Question 15

name a vasodilator that is a calcium channel blocker.

Answer 15

Verapamil
used for long-term & emergency
inhibits Ca2+ influx -> relaxation ->vasodilation
also inhibits cardiac Ca2+ channels
toxicity: bradycardia

Question 16

what is ACE?

Angiotensin converting enzyme

Answer 16

it converts angiotensin 1 to angiotensin 2 by inactivation bradykinin

Question 17

what is angiotensin 2, and what is its purpose

Answer 17

its a potent vasoconstrictor, and ˆ secretion of aldosterone and ADH

Question 18

what is bradykinin?

Answer 18

its a vasodilator that increases [NO] and results in relaxation of the muscle.

Question 19

what is aldosterone?

Answer 19

it increases Na+ reabsorption in distal tubules and collecting tubules (H2O will follow- osmosis)
ADH= antidiuretic hormone (vasopressin) increases the permeability of collecting ducts in kidney and increases the H2O reabsorption.

Question 20

name an ACE inhibitor and its side effects.

Answer 20

Enalapril: prodrug that metabolized to active drug.

S.E.: cough, hypotension, dizziness, heachache

Question 21

name an AT1 receptor Blocker (ARB). and its side effects

Answer 21

Losartan: effectiveness similar to ACE inhibitors, parent drug and metabolite active
S.E.: same as ACE inhibitor.

Question 22

what is a diuretic?

Answer 22

decreases BP by depleting body of Na+

Question 23

what diuretic could be use for mild-moderate hypertension? and how does it work?

Answer 23

hydrochlorothiazide
inhibits NaCL transport in distal convoluted tubule.
inexpensice and effective
toxicities: hypokalemia, gout, hyponatremia

Question 24

what diuretic should be used for more powerful hypertensions? and gow dies it work?

Answer 24

Furosemide
inhibits co-transporter of Na+, K+ and Cl- in loop of henle.
rapid and short acting
toxicities: can cause dose dependent ontotoxicity (hearing loss)

Question 25

what enhances the efficacy of diuretics?

Answer 25

ACE inhibitiors

Question 26

what are the clinical steps to treat hypertension?

Answer 26

Na+ restriction (low salt diet)
weight reduction
initial monotherapy:
-thiazide diuretic
-ACE inhibitor or ARB
-beta blocker, or Ca2+ channel blocker
-Alpha1 blocker, centrally acting sympatholytics

Question 27

what is combination step therapy, specifically what are the steps?

Answer 27

use in sever hypertension or if one group of drugs cannot control the hypertension. Done in this order:

1. diuretic
2. ACE inhibitor/ARB
3. Calcium channel blocker
4. sympatholytic/Vasodilator

Question 28

what are the problems associate with the combination therapy?

Answer 28

lack of patient compliance

but there is fixed-dose combinations available, only thing is that you cannot titrate individual drug doses if needed.