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Flashcards in Pharm 5 Lecture Deck (79):
1

What is the main sympathetic nervous system neurotransmitter?

Norepinephrine

2

What is released from the adrenal medulla (when stimulated by SNS) as a HORMONE?

Epinephrine

3

Catecholamines

hormones made by the adrenal glands, release when a person is under physical or emotional stress, high potency, quick duration, does not penetrate BBB, easily broken down, can't be taken orally

4

What are some examples of catecholamines?

Norepinephrine (Noradrenaline)
Epinephrine (adrenaline)
Dopamine
Dobutamine

5

What are the 6 steps of adrenergic neurotransmission?

1. Synthesis of norepi
2. uptake into storage vessicles
3. release of neurotransmitter
4. binding to receptor
5. removal of norepi
6. metabolism

6

What is the rate-limiting step of the synthesis of norepinephrine?

Hydroxylation of tyrosine into DOPA (dihyro-Phenoxyalanine)

7

What is the main precursor to epinephrine?

Dopamine

8

When is dopamine converted to norepinephrine?

Inside the vessicle; where it is protected from degradation

9

What inhibits transport of dopamine into the vessicle?

Reserpine

10

What causes fusion of the vesicle containing norepi with the cell membrane in a process known as exocytosis?

Influx of calcium causes the fusion

11

What blocks the release of the vesicle containing norepi?

Guanethidine and bretylium

12

What prevents reuptake of norepinephrine?

Cocaine and imipramine

13

What metabolizes norepineprhine?

Methylated by Catecol-O-methyl transferase (COMT)
Oxidized by Monoamine oxidase (MAO)

14

DOPA

dihydro-Phenoxyalanine

15

How does DOPA --> Dopamine?

Dopa is decarboxylated

16

Isoproteronol

A direct acting synthetic catecholamine

17

Alpha Adrenoceptors in order of affinity

Highest Affinity: Epinephrine
Norepinephrine
Lowest: Isoproterenol

18

Beta Adrenoceptors in order of affinity

Highest affinity: Isoproterenol
Epinephrine
Lowest: Norepinephrine

19

What are the names of the dopaminergic receptors?

D1, D2, D3, D4, D5

20

A1 receptors have a relatively high affinity for....

Norepinephrine

21

A2 receptors have a high affinity for....

Clonidine (Catapres), an antihypertensive drug

22

What does alpha 1 innervate?

Smooth muscle of most non-cardiac origin

23

What are the effects of stimulating alpha 1?

vasoconstriction; increased bp
mydriasis (dilation of pupils)
increased bladder tone
increased tension in prostate

24

What are the effects of stimulating alpha 2?

Creates negative feedback loops (prejunctional nerve terminals)
Some GI and digestive effects

25

Where are alpha 2 receptors located?

Prejunctional nerve terminals

26

Why would we stimulate alpha 2?

Increasingly used in human cardiovascular surgery as a sedative as part of multi-modal anesthesia

27

What are some advantages to stimulating alpha 2 during srugery?

Modulates DPB-induced inflammatory responses better than glucocorticoids (such as a cortisol)

Sympatholytic effects help ameliorate unwanted CV reflexes post-op

less respiratory depression postop than other options

28

What is the one alpha 2 drug used in humans?

Dexmedetomidine (precedex)

29

What has affinity for Beta 1 receptors?

Equal affinity for norepinephrine and epinephrine (both less than isoproterenol)

30

What has affinity for Beta 2 receptors?

More affinity for epinephrine than norepinephrine
Both again, have more affinity than isoproterenol

31

What are Beta 3 receptors involved in?

Lipolysis

32

What tissues have beta 1 receptors?

Many, but mostly in the heart!

33

What are the effects of beta 1 stimulation?

Positive chronotrope
Positive ionotrope
Increased lipolysis (triglycerides feed heart)
Kidneys release more renin (vasoconstriction, increase bp)

34

What do beta 2 receptors mostly affect?

lungs

35

What are the effects of beta 2 stimulation?

Mostly relaxation of pulmonary smooth muscle
vasodilation in skeletal muscles and liver and some organs
insulin release (energy jolt)
uterine muscle relaxation
increased liver output metabolic food via glycogenolysis

36

What is the effect of stimulating dopaminergic receptors?

Positive chronotrope
Positive ionotrope
vasoconstriction (at high doses)
increased blood flow to the kidneys

37

What acts as both a hormone and neurotransmitter?

Epinephrine

38

What does epinephrine stimulate?

alpha and beta; the archetypical adrenergic response

39

What are the effects of epinephrine?

Positive inotrope and chronotrope (B1)
Kidneys release renin, results in vasoconstriction, bp (B1)
Increased CO and O2 consumption

Dilates arterioles to liver and skeletal muscle (B2)
Bronchodilation (B2)
Pancrease releases glucagon; increase gluconeogenesis; the creation of glucose; hyperglycemia (B2)

Constricts arterioles to mucous membranes, viscera, skin (A1)

40

What does epi affect at low doses?

Beta affects predominate

41

What does epi affect at high doses?

alpha effects

42

How is epinephrine administered?

IV, IM, SQ, endotracheally (not orally)

43

What degrades epinephrine?

Monoamine oxidase
catechol-o-methyl transferase

44

CPR dose of epinephrine

1mg IV/IO every 3-5 min

45

What is epi used for?

Hypotension and shock
Anaphylaxis and shock Type I hyeprsensitivities
Asthma /bronchoconstriction
In conjunction with local anesthetics (like lidocaine)

46

What are the perfusion doses of epinephrine for an adult?

2-10 ug bolus PRN to effect

1-10 ug/min infusion given to effect

47

What are the perfusion doses of epinephrine for a ped?

0.05-10 ug/kg bolus

0.05-0.5 ug/kg/min infusion

48

What adrenoreceptors does norepi affect?

Alpha and Beta 1
(little effect on beta 2)

49

What are some other names for norepinephrine?

Noradrenaline
Norepinephrine
Levarternol

50

What are the cardiovascular effects of norepi?

Profound vasoconstriction (Alpha) w.o B2 effects
Both systolic and diastolic BP's increase
increase SVR

Positive inotrope (B1) but little chronotrope

51

Why is there little chronotropic effect of norepinephrine?

Baroreceptor reflex arcs; increase parasympathetic stimulation which decreases HR, decreases sympathetic stimulation which decreases HR and SV. Vasodilation decreases HR and SV and tried to bring BP to normal

52

How is norepinephrine administered?

Generally given by bolus or more commonly, infusion
short half life

53

What is the adult dose of norepinephrine?

0.5- 12.0 mcg/min titrated to effect

54

Why can't you give norepinephrine Sub Q?

Causes necrosis

55

What do high doses of dopamine affect?

Alpha receptors, arterial and venous vasoconstriction

56

What do low doses of dopamine effect?

Beta receptors; vasodilation to kidneys, brain and viscera

57

What are the effects of dopamine?

Positive inotrope and chronotrope (B1)
Vasoconstriction at high doses (A1)

Increase renal blood flow (D receptors)
Increased visceral perfusion (D receptors)

58

What do medium doses of dopamine effect?

increased cardiac output

59

What are the high, medium, and low doses of dopamine?

Low: 1-2 mcg/kg/min
Medium: 2-10 mcg/kg/min
High: >10 mcg/kg/min

60

What is the drug of choice for cardiogenic or septic shock?

Dopamine

61

What is dopamine used to treat?

Cardiogenic or septic shock
Renal failure
Hypotension (particularly low output renal failure)
CHF (particularly low output renal failure)

62

What is the synthetic analog of dopamine?

Dobutamine (Dobutrex)

63

What receptors does dobutamine work on?

B1 selective agonist

64

How does dobutamine compare to dopamine?

Dobutamine has greater inotropic and less chronotropic effect than dopamine (increases SV, CO)

65

What is the half life of dobutamine?

10 minutes with IV infusion; short half life

66

What is the dobutamine dose?

2-20 mcg/kg/min to effect (with HR not increasing >10% above baseline) in adults

2.5-10 mcg/kg/min in pediatrics

67

What is an advantage of dobutamine?

Causes less increase in myocardial O2 demand than the other catecholamines mentioned so far

68

What is dobutamine used for?

Short-term support of patients with CHF, as in struggling to separate from bypass

69

What is like dobutamine, but a PARTIAL B1 selective agonist?

Prenalterol
Both PO and IV used with a long duration of action (unlike isoproternol)

70

Isoproterenol (Isuprel)

Synthetic catecholamine B1 and B2 selective agonist

71

What are the effects of Isuprel?

Strong positive chronotrope and positive inotrope and a potent vasodilator B2)

Increases CO and decreases afterload

72

When is Isuprel used?

Mostly used as a cardiac stimulant in emergency situations (usually as a 2nd-line drug)

73

Neo

Relatively alpha 1 selective agonist
Potent vasoconstrictor, raises SBP/DBP, increase SVR
Causes reflex bradycardia
Can treat SVT

74

Why does neo have a longer DOA?

not a catecholamine derivative therefore not inactivated by COMT

75

Why is Neo commonly used as a nasal spray decongestant?

Phenylephrine decreases nasal congestion by acting on alpha 1 adrenergic receptors in the arterioles of the nasal mucosa to produce constriction.

76

What is dose of neo?

Adult: 50-200 ug repeated and given to effect
Peds: 0.05-0.5 ug/kg

77

"Mixed Action" Adrenergic Agonists

Ephedrine (vasopressor) and Pseudoephedrine

Sympathomimetics: cardiac stimulation, elevated systolic and diastolic BP's, CNS stimulation, bronchodilation

78

What drug is metabolized into dopamine?

Levodopa (which doesnt cross the BBB)

79

What are dopaminergic agonists used for?

treating Parkinson's Disease, cause by degeneration of dopamine- producing cells in the brain