Lecture 16 - Adrenergic blocking agents Flashcards Preview

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Flashcards in Lecture 16 - Adrenergic blocking agents Deck (65):
1

What are the alpha-receptor blockers? (two)

Phentolamine
Phenoxybenzamine

2

What are the Alpha1 blockers? (one)

Prazosin

3

What is the alpha2 blocker?

Yohimbine

4

What are the beta blockers? (three)

Propranolol
Timolol
Sotalol

5

What are the beta1 blockers?

Metoprolol
Atenolol

6

What is the general distribution of alpha receptors?

Blood vessels

7

What does alpha 1 cause?

Mydriasis
Vasoconstriction
Contraction of genitourinary muscle
Ejaculation

8

What does alpha2 cause?

decrease NE release
Suppress insulin secretion

9

What does alpha blockade do you cardiovascular system?

Decrease peripheral resistance = Decrease D pressure
= decrease BP
Decrease venous return = othrostatic hypotension

10

What does alpha blockade do to the eyes?

Miosis (via lack of radial muscle stimulation)

11

What happens to the nasal passages with alpha blockade?

Nasal congestion due to decreased vasoconstriction

12

What happens to urinary flow with alpha blockade?

urine flow increases
Base of bladder + urinary sphincter + prostate relax

13

What happens to sexual reproduction with alpha blockade?

Ejaculation inhibited

14

What do alpha2 blocking agents do?

Increase NE release

15

What is the basic distribution of beta receptors?

Heart

16

What does the B1 receptor do? (two things)

Increase heart rate and force
Increase renin secretion

17

What does B2 stimulation cause? (four things)

Relax bronchioles
Dilate BV supplying skeletal muscles
Increase glycogenolysis
Increase aqueous humor + intraocular pressure

18

What does B2 stimulation cause?

Lipolysis

19

What are the basic three things that occur with beta blockade in the heart and kidney ?

Decrease in HR and force
Decrease in CO and O2 demand
Decrease in renin secretion

20

What will happen overtime with beta blockade?

Decrease in BP in patients with hypertension

21

What does beta blockade cause with metabolism?

Decrease glycogenolysis + lipolysis

22

What is the behavior of a competitive antagonist?

If enough agonist is present can reach Emax

23

What is the behavior of a non-competitive antagonist?

Emax is lowered, no matter the concentration of the agonist

24

What are the competitive, reversible alpha antagonists?

Phentolamine + Prazosin

25

What is the irreversible, non-competitive alpha antagonists?

Phenyoxybenzamine

26

What are the six major things that occur with alpha blockade?

Reduced vasoconstriction
Reflex tachycardia
Miosis
Nasal stuffiness
Decreased resistance to urinary flow
Inhibition of ejaculation

27

What occurs once vasoconstriction is reversed with an alpha blocker?

Baroreceptors sense decrease in BP and increase SNS output

28

Why does reflex tachycardia occur with an alpha blocker?

Decreased BP
Stimulates baroreceptors = increase NE release
NE --> Beta = Increased HR

29

What happens when you block the alpha effects of epinephrine?

Drop in BP due to lack of vasocontriction
Heart rate increase

30

What receptors does phentolamine target?

Alphas

31

What does phentolamine do?

Decrease diastolic BP + Peripheral resistance
Reflex tachycardia

32

What are the side effects of phentolamine?

Tachycardia + Arrythmia + Myocardial ischemia + Hypotension

33

When is phentolamine used?

Hypertensive crisis from pheochromocytoma or MAO inhibitors
Prevents necrosis after accidental injection of alpha agonist

34

What are the side effects of phenoxybenzamine?

Postural hypotension + Tachycardia
Nasal congestion + no ejaculation

35

When is phenoxybenzamine used?

NE/EPI levels are too high and can overcome the effects of a drug that was a competitive agonist

36

When is phenoxybenzamine used?

Small animals with detrusor areflexia

37

What is a pheochromocytoma?

Adrenal neoplams that secretes NE/EPI

38

What is the treatment of a pheochromocytoma?

treat with phenoxybenzamine then surgery

39

What is a sign there is a pheochromocytoma?

Sudden onset of severe hypertension + tachycardia + arrhythmia

40

What do you test for in the urine to see if a pheochromocytoma is a possibility?

VMA

41

What does prazosin target?

Alpha 1

42

What does prazosin do?

Relax arterial + venous SM = decreased peripheral resistance
Decrease venous return = decrease preload

43

What is an upside to using prazosin?

no alpha2 so less tachycardia

44

What are side effects of prazosin?

Dizziness + Lethargy

45

When is prazosin used?

CHF
Functional urethral obstruction

46

What does yohimbine target?

Alpha2

47

What does Yohimbine do?

Increase NE release = increase BP and HR
Increased motor activity

48

What is a side effect of yohimbine?

tremors

49

What can yohimbine be used for in animals?

Reverse effects of xylazine

50

What does beta blockade cause in the lungs?

Bronchoconstriction

51

Where should you never use a beta blocker?

Horses with RAO

52

What does a B blocker do in the eye?

Decrease formation or aqueous humor

53

What does chronic use of a beta blocker do in regards to metabolism?

increase VLDL + decrease HDL

54

What beta blockers have the ability to be a local anesthetic?

Proranolol + Metoprolol

55

How does metoprolol + propranolol have local anesthetic capabilities?

Membrane stabilizing via sodium channel blockade

56

What are the effects of propranolol?

Decrease HR + Contractility
Decrease renin + lipolysis + glycogenolysis

57

What are the pharmokinetic characteristics of propranolol?

Low bioavalibility
Lipid soluble = CNS activity = sedation

58

What is the major side effect of propranolol?

Bronchoconstriction

59

What is another medication similar to proprananol?

Timolol

60

How does timolol differ from proprananol?

No local anesthetic affect
= can be used in eye

61

What other symptoms are seen with proprananol use?

Bradycardia
Increase symptoms seen with CHF
Lethargy
Decrease excercise tolerance (B2 blockade, muscles sad)
Increase glucose levels

62

What happens with abrupt discontinuation of propranaol

Tachycardia + Arrhythmia

63

What are your two Beta1 selective blockers?

Metoprolol + Atenolol

64

What is the effect of metoprolol + atenolol?

Heart mostly
Decrease HR + Contractility
Decreased O2 demand
Decreased renin secretion
= DECREASE BP

65

What is metoprolol + atenolol used for?

Hypertension + Tachycardia + Arrhythmia