2.4 Hypertension - Direct vasodilators

Question 1

What is the difference in effect of dilating arterioles vs. dilating veins?

Answer 1

Dilating arteries will decrease systemic vascular resistance and i_ncrease cardiac output._

In contrast, dilating veins allows pooling in the venous system, decreasing pre-load, which decreases stroke volume and lowers cardiac output.

Question 2

What does hydralazine do?

What is it used to treat?

SEs?

Answer 2

Note: a rare but significant SE is a syndrome that looks like Lupus (joint pain etc)

Question 3

What does minoxidil do?

What is it used to treat?

SEs?

Answer 3

(O) SE: hypertrichosis (hair growth– used beneficially as rogaine)

Risk of pericardial effusion (black box warning)

Question 4

1. What is the effect of Sodium Nitroprusside (Nipride)?
2. What is it used to treat?
3. What is its route of administration?
4. What are its two metabolites?
5. Notable concerns?
6. Notable SEs?

Answer 4

1. Dilates both arterioles and veins
2. Reduces PVR and venous return to decrease hypertension
3. IV only
4. NO and Cyanide are both metabolites
5. long-term use can lead to cyanide poisoning.
6. Delayed hypothyroidism

Question 5

1. What is the effect of Calcium channel blockers?
2. What do they treat?

Answer 5

1. They inhibit Ca influx into the arterial smooth muscle, causing arterial vasodilation and decreased PVR (pulmonary vascular resistance– the resistance in arteries that supply blood to lungs). It also dilates coronary arteries
2. HTN

Question 6

What are the dihydropyridines?

What tissue do they select for?

What are they used to treat?

Adverse effects?

Answer 6

Question 7

What are verpamil and diltiazem?

What are their effects?

What tissue do they select for?

What is their typical use?

Answer 7

Question 8

The major pharmacologic difference between the dihydropyridine Calcium Channel Blockers and Verapamil is:

Answer 8

Verapamil is more cardioselective

Question 9

Differences between sodium nitroprusside (nipride) and hydralazine & minoxidil include all of the following EXCEPT

• Nipride dilates both arteries and veins; hydralazine and minoxidil dilate only arterioles
• Nipride is exclusively available as an IV formulation
• Prolonged use of nipride can lead to cyanide poisoning
• Hydralazine and minoxidil have no significant adverse effects

Answer 9

Hydralazine and minoxidil have no significant adverse effects