NE, Dopamine, Isoproterenol, Dobut, Ephedrine and Phenylephrine.

Question 1

What is the dose for NE for hypotension?

Answer 1

4-16mcg/min

Question 2

Where is NE most potent?

Answer 2

Alphas and B1

Question 3

What receptor does NE have a minimal effect on?

Answer 3

B2

Question 4

Because NE has minimal B2 effects what four events result?

Answer 4

1. Intense vasoconstriction of the skeletal muscles, liver, kidneys, cutaneous tissue (at risk for metabolic acidosis)
2. Increased SBP, DBP, MAP
3. Baroreceptors are activated which DECREASES HR and decrease respiration in a patient breathing for themselves
4. Decreased venous return, CO, HR (despite B1 effect)

Question 5

Dopamine is the endogenous precursor of?

Answer 5

NE

Question 6

Which receptors does DA stimulate?
Same potency?
In what other way can it work?

Answer 6

1. All adrenergic including DA receptors.
2. Not at the same potency
3. Also works by increasing the release of NE from vesicular stores.

Question 7

At what dose of DA are we mainly stimulating D1 receptors?

Answer 7

1-3mcg/kg/min

Question 8

At what dose of DA are we mainly stimulating B1 receptors?

Answer 8

3-10mcg/kg/min

Question 9

At what dose of DA are we mainly stimulating Alpha receptors?

Answer 9

> 10mcg/kg/min

Question 10

Are dosing ranges a reliable predictor of expected plasma concentration of DA?

Answer 10

No.

Question 11

Can DA be given PIV?

Answer 11

Dangerous if it infiltrates.

Question 12

What six things does DA increase?

Answer 12

1. Myocardial contractility
2. Renal blood flow
3. Urine output
4. GFR
5. Endogenous release of NE
6. IOP

Question 13

What drug can be used with DA to synergistically reduce afterload and improve cardiac output?

Answer 13

Dobut

Question 14

Where is DA inhibitory?

What will the patient have an altered response to?

Answer 14

1. Carotid bodies

2. Hypoxia.

Question 15

At which receptors does Isoproterenol act?

Answer 15

Selective B1 and B2 agonist. Pretty much equally.

Question 16

What does Isoproterenol do to HR, contractility, SVR, SBP, DBP and MAP?

Answer 16

Increased HR, contractility and SBP (B1)

Decreases SVR, DBP and MAP (B2)

Question 17

What is the dose of isoproterenol and when is it used?

Answer 17

1-5mcg/min for HB and bradydysrhythmias. At doses higher than this we would have supply vs. demand issues.

Question 18

How is isopproterenol metabolized?

Answer 18

It is a synthetic catecholamine so by COMT. Need an infusion.

Question 19

What kind of patient is at risk with use of isoproterenol?

Answer 19

CAD

Question 20

What is the dose range for dobutamine?

Answer 20

2-10 mcg/kg/min

Question 21

Under 5mcg/kg/min where is dobutamine selective?

Answer 21

B1! However, weak activity at the SA node gives us an assist with contractility without a huge increase in HR.

Question 22

Over 5 mcg/kg/min where will dobutamine have weak stimulation?

Answer 22

Alpha 1

Question 23

Why do we like dobutamine in CHF?

Answer 23

Improves CO without increasing HR or BP substantially.

Question 24

Where dose dobutamine vasodilate?

Answer 24

The coronary arteries.

Question 25

How and where does ephedrine work?

Answer 25

Indirect and direct agonist at alpha and beta receptors. All four receptors.

Question 26

How is ephedrine given?

Answer 26

IV, PO or IM

Question 27

What is the dose of ephedrine IV? and IM?

Answer 27

1. 10-25mg IV | 2. 10-50IM

Question 28

What do we see with repeated dosing of ephedrine?

Answer 28

Tachyphylaxis tolerance because of NE depletion. Receptor occupation because of a long half life.

Question 29

How is ephedrine metabolized and excreted? Half life?

Answer 29

1. Non-catecholamine so metabolized by MAO, conjugated in liver and 40% excreted unchanged in the urine. 2. 3 hours.

Question 30

Why can't ephedrine have direct B2 effects?

Answer 30

Because NE has minimal action at the B2 receptor.

Question 31

What kind of a stimulant is phenylephrine?

Answer 31

Primarily an alpha 1 adrenergic receptor stimulant.

Question 32

Where do we see the most constriction resulting from phenylephrine?

Answer 32

Venoconstriction more than arterial constriction giving us a nice boost in preload.

Question 33

Compare potency and DOA of phenylephrine to NE.

Answer 33

Phenylephrine is less potent but longer acting.

Question 34

What is the typical bolus IV dose of phenylephrine?

Answer 34

50-200mcg IV

Question 35

What is the typical infusion rate of phenylephrine?

Answer 35

20-50mcg/min

Question 36

How long does it take for phenylephrine to take effect?

Answer 36

1 minute

Question 37

Do we see an increase or decrease in HR with phenylephrine and why?

Answer 37

Decrease because of baroreceptor activity.

Question 38

What kind of an effect does phenylephrine have on MAP, SBP, DBP, SVR and CO?

Answer 38

Increases Map, SBP, DBP, SVR and decreases CO.