Chapter 21: Vascular Tone

Question 1

How do nitrates work?

Answer 1

NO activates guanylyl cyclase and increases DEphosphorylation of myosin light chain in vascular smooth muscle. This case vasodilation.

Question 2

What drug selectively dilates pulmonary vasculature?

Answer 2

Inhaled nitric oxide gas

(makes sense - INHALE/GAS/LUNGS!

Question 3

Which drugs dilate veins moreso than arteries?

Answer 3

Isosorbide dinitrate
Isosorbide 5 mononitrate
NTG

Question 4

Which drug targets arteries and veins equally by a non-enzymatic process? It is used for hypertensive emergencies.

Answer 4

Sodium nitroprusside.

Question 5

Which drug comes in a transdermal patch that you should remove at night to prevent tolerance and “Monday Morning headaches”?

Answer 5

NTG

Question 6

Why isosorbide 5 mononitrate preferred over dinitrate?

Answer 6

It has a longer half life, is absorbed better from the GI tract, less reboudn angina….

Question 7

Which nitrate is used for newborns with hypertension?

Answer 7

Inhaled nitric oxide gas

Question 8

How does NTG prevent coronary steal?

Answer 8

Preferentially dilates larger epicardial arteries than the smaller coronary arteries

Question 9

With what nitrate do you have a risk for cyanide toxicity?

Answer 9

Sodium nitroprusside (sounds like an evil little bitch…like the king of PRUSSia)

Question 10

What are nitrates typically used for? Short acting vs. long acting?

Answer 10

Acute angina attacks

Chronic heart disease

Question 11

When does cyanate toxicity become life threatening? concentration?

Answer 11

200mg/L

Question 12

SildenaFIL
VardenaFIL
TadalaFIL

Answer 12

MOA: Phosphodiesterase inhibitors (PDE5) leads to cGMP accumulation = smooth muscle relaxation

TX: ED

Question 13

Phosphodiesterase inhibitors are contraindicated when?

Answer 13

patients also taking organic nitrates NO NO NO DON’T DO ITTT

Also pts with a history of vision loss

Question 14

Sildenafil can be used to treat ED and what else?

Answer 14

pulmonary hypertension

Question 15

How do calcium channel blockers work?

Answer 15

They block voltage gated Ca channels so you prevent actin myosin cross bridge formation.

Question 16

Nifendipine

Answer 16

Ca channel blocker

Serious reflex tachycardia

Question 17

Amlodipine

Answer 17

Ca channel blocker

Higher bioavailability

Question 18

Felodipine

Answer 18

Ca channel blocker

Question 19

Clevidipine

Answer 19

Ca channel blocker

IV infusion for hypertension emergencies

Question 20

Which Ca channel blockers favor arterial vasodilation?

Answer 20

dyhydropyridines

Question 21

Diltiazem & verapamil

Answer 21

Ca channel blockers with less vascular to cardiac selectivity….

Use for Prinzmetal angina, hypertension, tachycardia

Verapamil w/alcohol makes alcohol more potent

Question 22

What Ca channel blocker has the most cardiac effect?

Answer 22

Verapamil (suppresses cardiac conductivity most)

Question 23

MOA potassium channel openers

Answer 23

open ATP modulated K channels and hyperpolarize the membrane –> inhibit influx of Ca –> decrease arterial BP

Question 24

Minoxidil
Pinacidil
Nicordandil

Answer 24

“Dil Pickle Potassium”

MOA: K channel opener
TX: severe hypertension or hair loss (ROGAINE!!!)
Use with beta blocker and diuretic to prevent reflect tachycardia

Question 25

How do you prevent reflex tachycardia when administering a K channel opener?

Answer 25

Give a Beta blocker also

Question 26

Rogaine is a —?

Answer 26

K channel opener! Dil

Question 27

Bosentan

Ambrisentan

Answer 27

“Sentan” –> Sun Tan –> endothelin gets TAN
MOA: endothelin receptor antagonist
TX: severe pulmonary hypertension
DO NOT use in preggo ladies

Question 28

Which endothelin antagonist has greater selectivity for ETa?

Answer 28

Ambrisentan

Question 29

Hydralazine

Answer 29

Dilates arteries
Mechanism unclear
TX: Moderate hypertension/severe heart failure
Hypertension: use with B blocker
Heart failure: use with nitro dinitrate

Question 30

Prazosin
Doxazosin
Terazosin

Answer 30

a-1 antagonists in venules and arterioles
but more in arterioles
= vasodilation
reduces arterial pressure - use to tx hypertension

Question 31

B blockers - what are they

Answer 31

b2 antagonists (propanolol, atenolol, LOLs)
relaxes smooth mm.
tx: hypertension, angina, cardiac craps
net effect = lower BP

Question 32

Captopril
Enalapril
Lisinopril

Answer 32

ACE inhibitors
inhibit cleavage of AT1 to AT2
Reduces BP

Question 33

Losartan

Valsartan

Answer 33

Block activatiion of AT1 receptors

“AT still is the sultan”