Cardio Drugs (Sympathemimetics )

Question 1

What are the alpha 1 sympathetic actions and what GPCR do they use

Answer 1

Increase:

pupillary dilation

vascular smooth muscle contraction of arterioles/ peripheral resistance/afterload

venoconstriction/ venous return/ preload

GI sphincter contraction

glycogenolysis

Bladder sphincter contraction: urinary retention

Ejaculation

Exocrine Gland Secretion

They utilize Gq

Question 2

what are the alpha 2 sympathetic actions and what GPCR do they use

Answer 2

Decrease

aqueous humor production

insulin release

lipolysis

sympathetic AdR outflow (Norepi release)

Increases: Platelet Aggregation

THESE USE Gi

Question 3

What are the beta 1 specific sympathetic actions and what GPCR do they use

Answer 3

Increase

heart rate via SA node stimulation

Conduction velocity via AV node/ purkinje fiber stimulation

Contractility via atria and ventricles

Renin release

Lipolysis

Question 4

What are the beta 2 specific sympathetic actions and what GPCR do they use

Answer 4

Increased

Aqueous humor production

bronchodilation

glycogenolysis

insulin release

detrusor relaxation of bladder

skeletal muscle contraction

lipolysis

cellular potassium uptake

Decreased:

uterine tone (tocolysis)

peripheral vasodilation/ peripheral resistance/ afterload

peristalsis

THESE USE Gs

Question 5

What are the beta 3 specific sympathetic actions and what GPCR do they use

Answer 5

Increased

Lipolysis

thermogenesis in skeletal muscle

bladder detrusor muscle relaxation

THESE USE Gs

Question 6

Presence of _ signals release od Dopamine from presynaptic dopaminergic neurons

Answer 6

tyrosine hydroxylase

Question 7

presence of _ signals the release of Norepi from presynaptic neurons

Answer 7

tyrosine hydroxylase

Dopamine B-hydroxylase

DOPA decarboxylase

Question 8

presence of _ signals the release of epinephrine from presynaptic neurons

Answer 8

tyrosine hydroxylase

Dopamine B-hydroxylase

DOPA decarboxylase

Phenylethanolamine-N-methyltransferase (PMNT)

Question 9

describe the breakdown of Norepi and Epi

Answer 9

COMT: degrades compounds into normetanephrine and metanephrine respectively

MAO: degrades normetanephrine and metanephrine onto Vanillymandelic acid

and Norepi/Epi into dihydroxymandelic acid

Question 10

State catecholamine preferences for receptors and explain the importance

Answer 10

Norepi: alpha receptors > beta receptors

Epi: beta receptors > alpha receptors

Alpha 1 receptors contract the vascular smooth muscle

Beta 2 receptors vasodilate

Explains why epi causes contraction of some blood vessels and dilates others

Question 11

albuterol

salbutamol

salmeterol

terbutaline

Answer 11

Beta 2 > Beta 1 agonist

used in obstructive lung diseases

preterm labor

Question 12

Clonidine

Answer 12

alpha 2/ imidazoline agonist

used for HTN, ADHD and drug withdrawl

Question 13

Dobutamine

Answer 13

Beta 1 > Beta 2 > Alpha receptor agonist

used in heart failure, cardiogenic shock and cardiac stress testing

Question 14

Dopamine

Answer 14

Direct and Indirect Receptor Agonist

D>B>a

used in heart failure

D receptors relax renal vascular smooth muscle

B receptors increased contractility, heart rate and conduction velocity

Question 15

carvedilol

Answer 15

Mixed Beta1/2 and alpha 1 blocker

alpha1 and beta1 blocking decreases PVR/ preload and BP

alpha 1 and beta 2 blocking decreases afterload and increases cardiac output

Also has antioxidant effects so that myocytes dont die of free radical damage to cause MI

Question 16

isoproterenol

Answer 16

Beta > alpha agonist

increases cardiac contractility,HR and AV conduction velocity while increasing dilating vessels due to B2 agonization

used in bradycardia/ heart block and cardiac arrest from heart block when pacemaker therapy is unavailable

Question 17

labetalol

Answer 17

Nonselective B blocker and alpha 1 blocker

beta blocking decreases heart rate and cardiac output

alpha blocking decreases vascular smooth muscle contraction PVR/ afterload and venoconstriction/ venous return/ preload

Question 18

metoprolol

Answer 18

selective beta1 blocker

indicated by coronary heart disease, compensated heart failure, ACS and cardiac arrhythmias

Blocking beta1 decreases cardiac contractility, heart rate and AV conduction velocity

Question 19

phenoxybenzamine

Answer 19

Noncompetitive Nonselective Alpha antagonist

used in pheochromocytoma

not useful in HTN due to reflex bradycardia

Question 20

phentolamine

Answer 20

Competitive Nonselective Alpha antagonist

used in pheochromocytoma

can be used to counteract local ischemia caused by accidental digital epi sticks, as it competes with epi at the alpha-AdR

Question 21

prazosin

Answer 21

alpha 1 blocker

used in ADHD and PTSD

Question 22

propranolol

Answer 22

beta blocker that competitively blocks the effects of Norepi and other AdR agonists

Used in: HTN, angina pectoris

arrythmias. essential tremor, MI, pheochromocytoma, acute thyrotoxicosis and hypertrophic subaortic stenosis

Question 23

Compare and contrast phenoxybenzamine and phentolamine

Answer 23

phenoxybenzamine is long acting

phentolamine is short acting and can be used in the event of accidental epi sticks