Vasodilators

Question 1

What are the major classes of vasodilators?

Answer 1

Ca blockers

Nitric oxide

Direct vasodilators

Open K channels

Question 2

Name the direct vasodilator and what is it used to treat.

Answer 2

Hydralazine

Treats hypertension

Question 3

How was the direct vasodilator hydralazine work?

Answer 3

Direct muscle relaxation on resistance vessels

Dilates arterioles (NOT veins) -> Dec TPR

Question 4

What are the adverse affects of hydralazine?

Answer 4

Reflex tachycardia

Lupus type reaction (butterfly rash)

Question 5

Name two vasodilators that acts on K channels.

Answer 5

Minoxidil and Diazoxide

Question 6

What is minoxidil used to treat?

Answer 6

Hypertension, HT, baldness

Question 7

How does minoxidil work?

Answer 7

Opens K channels in smooth muscles

Dilates arterioles (NOT veins)

Muscle relaxation via stabilization of membrane at its resting potential

Question 8

What is a common adverse effect of the vasodilator minoxidil?

Answer 8

Hair growth

Reflex tachycardia

Question 9

Name a vasodilator that acts by increasing release of nitric oxide.

Answer 9

Nitroprusside

Question 10

How does nitroprusside act as a vasodilator?

Answer 10

Activates guanylyl cyclase -> Inc cGMP -> Inc NO -> Muscle vasodilitation of arterial AND venous vessels

Question 11

What does nitroprusside treat?

Answer 11

Acute EMERGENCY HT and CHF (not long term, only emergency, one or two days to reduce BP)

Given IV

Question 12

How is nitroprusside administered?

Answer 12

IV (oral administration can lead to cyanide poisoning)

Question 13

What are the side effects of nitroprusside?

Answer 13

Arrhthmias (Inc HR)

Reflex tachycardia

Cyanide toxicity

Methemoglobinemia, metabolic acidosis (doesn’t bind to oxygen -> poor oxygen saturation)

Question 14

Name an alternative drug to nitroprusside?

Answer 14

Fenoldopam

Question 15

Why is fenoldopam an alternative to nitroprusside?

Answer 15

Both drugs act to reduce EMERGENCY HT via IV, but fenoldopam has no cyanide

No cyanide

No methhemoglobinemia

Question 16

What is fenoldopam used to treat?

Answer 16

EMERGENCY HT

Question 17

How does fenoldopam act?

Answer 17

Dopamine agonist (D1A receptor) -> Dec TPR

Question 18

What are the benefits of fenoldopam over nitroprusside?

Answer 18

Fenoldopam has no cyanide

Doesn’t lead to methhemoglobinemia

Question 19

What is diazoxide used to treat?

Answer 19

Acute hypertensive crisis

Maybe hypoglycemia

Question 20

How does diazoxide work?

Answer 20

Similar to minoxidil Opens K channels in smooth muscles, dilates arterioles (NOT veins), muscle relaxation via stabilization of membrane at its resting potential

Lowers TPR (reflex inc HR and CO)

Question 21

How is minoxidil different from diazoside in terms of what they treat?

Answer 21

Minoxildil treats CHRONIC HT not emergency HT

Question 22

Why is diazoside used to treat HYPOglycemia?

Answer 22

Inhibits insulin release

Question 23

What two drugs are used to treat hypertensive crisis?

Answer 23

Nitroprusside and Diazoside

Question 24

Both nitroprusside and diazoside treat a hypertensive crisis. What is the difference between them?

Answer 24

Nitroprusside increases NO production

Diazoside opens K channels (mechanism similar to Minoxidil)