Vasodilators

Question 1

Why are vasodilators used in the treatment of heart failure?

Answer 1

Use of vasodialators decreases the preload and/or afterload placed on the heart

Question 2

Venodilators reduce the (preload or afterload) on the heart.

Arteriodilators reduce the (preload or afterload) on the heart.

Answer 2

Venodilators- preload

Arteriodilators- afterload

General vasodilators do both

Question 3

Are nitrates vasodilators, venodilators, or arteriodilators?

What is their mechanism of action?

Answer 3

Venodilators

Bind to nitrate receptor on endothelial cells -> enter cell -> conversion to nitric oxide (NO) via interaction with thiol groups -> increase in cGMP -> reduction in Ca influx -> relaxation/dilation

Question 4

Nitroglycerin belongs to what class of vasodilators?

Answer 4

Nitrates- venodilators

Question 5

Nitroprusside belongs to what class of vasodilators?

Answer 5

Nitrates- balanced vasodilators (per lecture)

Question 6

What are the therapeutic uses of nitroprusside?

Answer 6

Decrease systemic blood pressure in congestive heart failure secondary to mitral regurgitation and dilated cardiomyopathy

Question 7

How does nitroprusside differ from other vasodilators in the nitrate group?

Answer 7

Directly converted to NO without involvment of thiol groups

Question 8

How does reducing afterload improve cardiac function?

Answer 8

Decreases pressure and wall stress in the heart, increasing contractility and therefore stroke volume

Question 9

Sildenafil is a vasodilator that selectively acts in which area of the body?

What is its mechanism of action?

Answer 9

Selectively dilates pulmonary vasculature

Inhibits phosphodiesterase-5, found mostly in bronchi and trachea, preventing breakdown of cGMP

Question 10

What are the therapeutic uses of sildenafil?

Answer 10

Moderate to severe pulmonary hypertension in dogs