Exam II: Adrenergic Agonists Flashcards Preview

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Flashcards in Exam II: Adrenergic Agonists Deck (93):
1

The general term for neurotransmitters/hormones in the sympathetic nervous system is:

Catecholamines

2

What are the 3 major catecholamines?

Dopamine
Norepinephrine
Epinephrine

3

What are the 4 basic adrenergic receptors?

alpha 1
alpha 2
beta
dopamine

4

Alpha 1 receptors are coupled with ____ proteins and produce ____ effects

Gq proteins

Activate other enzymes, resulting in positive effects

5

Alpha 2 receptors are coupled with ____ proteins and produce ____ effects

Gi proteins

Decrease cAMP causing negative action

6

Beta receptors are coupled with ____ proteins and produce ____ effects

Gs proteins

Inc. conversion of ATP to cAMP (inc. cAMP)

7

Dopamine receptors are coupled with ____ proteins and produce ____ effects

Gi and Gs

D1: increase cAMP
D2: decrease cAMP

8

What are the 4 factors that can alter the degree to which adrenergic receptors respond to a stimulus

1. Selectivity
2. Regulation
3. Polymorphism
4. Catecholamine metabolism

9

What are the 4 examples of mechanisms of desensitizations?

1. Altered transcription or translation of DNA and/or RNA

2. Modifications of receptors

3. Long term exposure to an agonist

4. Interactions or messages from other receptors

10

How is NE terminated in the cell? (4 ways)

1. NET acts as pre-synaptic pump to move NE out of synapse and back into neuron

2. Movement of NE out of synaptic cleft and into bloodstream

3. Metabolism b COMT

4. Metabolism by MAO

11

What are 2 drugs that inhibit NET?

Atomoxetine (for ADHD)

Cocaine

12

What does COMT stand for?

catecholamine-O-methyltransferase

13

What does COMT metabolize?

All catecholamines (NE, Epi, DA)

14

What is a drug that inhibits COMT and what disease is it used to treat?

Entacapone

Treats Parkinson's dz to inhibit metabolism of levodopa

15

What does MAO stand for?

Monoamine Oxidase

16

What does MAO metabolize?

Endogenous monoamines (NE, epi, serotonin, DA)

17

Define sympathomimetic

Drugs that mimic actions of NE, epi, DA

18

Where on the chemical structure can changes be made to sympathomimetics to alter affinity?

1. Benzene Ring Substitutions
2. Amino group substitutions
3. Alpha carbon substitutions
4. Beta carbon substitutions

19

Describe possible benzene ring substitutions

1. Adding hydroxyl groups to C3 and C4
2. Adding a hydroxyl group to either C3 or C4
3. Absence of hydroxyl group on benzene ring

20

If a sympathomimetic has -OH groups added to C3 and C4 position of the benzene ring then what characteristics would you expect?

Maximized alpha and beta activity

Susceptible to COMT breakdown so they will have a shorter half-life

21

If a sympathomimetic has an -OH group added to either C3 or C4 position of the benzene ring then what characteristics would you expect?

Reduced adrenergic potency

COMT can NOT break down so inc. drug duration

22

If a sympathomimetic has no -OH groups on its benzene ring then what characteristics would you expect?

Lipophilic --> can enter CNS

23

Describe the possible amino group substitutions

Increasing the size of alkyl substitutions

Isopropyl groups on the amino nitrogen

24

What does increasing the size of an alkyl substitution do to the sympathomimetic drug?

Increases beta activity

The larger the group, the lower the alpha activity

25

What does adding an isopropyl group to the amino nitrogen do to the sympathomimetic drug?

Increases beta activity

26

What do substitutions to the alpha carbon of a sympathomimetic cause?

They block oxidation by MAO and therefore have a prolonged duration of action

27

What can adding a methyl group to the alpha carbon do?

Increases drugs ability to act as an indirect sympathomimetic and a direct sympathomimetic

28

What is an example of a drug with a methyl group added to the alpha carbon?

Amphetamine

29

The outcome of giving a drug is dependent upon 3 things:

1. Selectivity for alpha and beta receptors
2. Pharmacologic action at the receptors (at/antag)
3. Action of body's compensatory mechanisms to maintain homeostasis (ie: desensitization)

30

Where are alpha 1 receptors located in the cardiovascular system?

Vascular beds

31

When an alpha 1 receptor is activated in the CV system what occurs?

Arterial and venous vasoconstriction --> inc. BP, a reflexive slowing of HR, but venous return also increases which increases stroke volume and maintains CO

(CO= HR x SV)

32

Name a drug that activates alpha 1 receptors in CV system. What does it treat?

Phenylephrine

Maintain BP in pt w/ poor organ perfusion
Treat stuffy nose (neosenephrine)

33

Where are alpha 2 receptors located in the CV system?

Vascular beds and CNS

34

When the peripheral alpha2 receptors are activated what occurs?

Vasoconstriction -- but only when given locally, IV push, or very high oral doses

35

When the central alpha 2 receptors are activated what occurs?

A decrease in sym. activity --> dec. BP

*Needs to be given systemically

36

What is a therapeutic use involving alpha 2 receptors....what drug is commonly used?

Hypertension

Clonidine

37

If a beta 1 receptor is activated then what CV effects will be seen:

Inc. HR --> inc. CO

38

If a beta 2 receptor is activated then what CV effects will be seen?

Dec. BP

39

What does stimulation of dopamine 1 receptors do in terms of the CV system?

Vasodilation

40

Dopamine also binds to ____ and ____ receptors.

Alpha and beta

41

A low dose of dopamine....

activates beta 2 receptors

42

A medium dose of dopamine....

activates beta 1 receptors

43

A high dose of dopamine...

activates alpha 1 receptors

44

What receptors are present in the lungs and what does stimulation of these receptors cause?

Beta 2 receptors --> bronchodilation

45

What receptors are present in the eyes and what does stimulation of these receptors cause?

Alpha receptors (in radial muscle) --> mydriasis

46

What receptors are present in the GU system and what does stimulation of these receptors cause?

Alpha receptors (in bladder, sphincter, prostate, etc) --> promotes urine retention and ejaculation

47

What receptors are present in salivary glands and what does stimulation of these receptors cause?

Beta receptors --> inc. salivation

48

Sympathomimetics ______ glycogenolysis in liver via ______ _________.

Increase
Beta Receptors

49

____ receptors increase lipolysis while ____ receptors decrease lipolysis.

Beta
Alpha 2

50

____ receptors increase release of renin while ___ receptors decrease release of renin

Beta 1
Alpha 2

51

Besides insulin and renin, what are 4 other hormones mediated by adrenergic receptors:

1. Parathyroid hormone
2. Calcitonin
3. Thyroxine
4. Gastrin

52

Epinephrine is an agonist at ____ and ____ receptors

alpha and beta

53

Epi causes a ____ in systolic BP due to _____. And it also ____ HR and CO due to _____.

Increase
Alpha 1
Increases
Beta 2

54

NE causes an ____ in systolic BP due to ____. It also ____ HR and CO via _____.

increased
Alpha 1
Increased
Beta 1

55

Phenylephrine

Direct alpha 1 agonist

Not inactivated by COMT...longer duration

Used as a decongestant and to raise BP

56

Midodrine

Direct alpha 1 agonist (a prodrug...its hydrolyzed form is actually the alpha 1 agonist)

Inc. BP and treats orthostatic hypotension

57

Name the 4 drugs that act as alpha 2 agonists and reduce blood pressure, treating HTN

"Gross Men Chew Gum"

Guanfacine
Methyldopa
Clonidine
Guanabenz

58

What is dexmedetomidine used for? What type of sympathomimetic drug is it?

Acts in the CNS and used for sedation of patients in the ICU setting

Direct Alpha 2 Agonist

59

What is an example of a direct alpha (1 and 2) agonist?

Oxymetazoline

60

What does oxymetazoline do?

Alpha 1 action causes vasoconstriction and used as a decongestant

Alpha 2 reduces BP

61

Name a non-selective beta agonist

Isoproterenol

62

Isoproterenol: effects and what it is used for

Vasodilation (beta 2) --> dec. BP and mean arterial pressre

Positive chronotropic and inotropic effects (beta 1) --> inc. HR and CO

Variety of effects so not really used

63

_____ is a beta 1 selective agonist.

Dobutamine

64

Describe the actions of the two dobutamine isomers

(+) isomer: Beta 1 agonist, alpha 1 antagonist
--> Inc. CO w/o increase BP

(-) isomer: Alpha 1 agonist
--> Inc. BP

*When given together = positive inotropic effect w/ little change in BP

65

What type of sympthomimetics are used to treat asthma and COPD?

Beta 2 selective agonists

66

What type of sympathomimetics are used to relax uterine smooth muscle during labor?

Beta 2 selective agonists

67

List the drugs used to treat asthma and COPD

"Albert Met Soloman Teaching Pilates Form"

Albuterol
Metaproterenol
Salmeterol
Terbutaline
Pirbuterol
Formoterol

68

What is the drug (beta 2 selective agonist) used to relax uterine smooth muscle during early labor?

Ritodrine

69

How would one classify ephedrine (pseudoephedrine)

Mixed-acting sympathomimetic

AKA: provides effects of alpha and beta receptors

70

What are the two mechanisms in which indirect-acting sympathomimetics act?

1. They displace stored catecholamines
2. Inhibit reuptake of released neurotransmitter by interferring w/ NET

71

What do amphetamines release and what is their action within in the CNS system?

Cause release of NE and DA

They are a CNS stimulant meaning they inc. mood and alertness while dec. appetite

72

What are the 3 amphetamine derivatives?

1. Methamphetamine (crystal meth)

2. Phenmetrazine

3. Methyphenidate (Ritalin)

73

How does methyphenidate work? (aka what does it treat)

(Ritalin) reduces reuptake of NE, improving its function in the brain in order to treat ADHD

74

What two drugs can be used to treat patients w/ narcolepsy, obstructive sleep apnea, and shift work disorder?

What class are these drugs?

Modafinil and Armodafinil

Indirect acting sympathomimetics

75

Patients taking an MAO inhibitor need to be warned not to consume ______ because of _______.

tyramine containing foods (aged foods)
Potentially dangerous HTN

76

Describe tyramine actions

Causes release of stored catecholamines...similar actions to NE (alpha 1, alpha 2, beta 1)

77

4 examples of catecholamine reuptake inhibitors:

1. Atomoxetine
2. Subutramine
3. Doluxetine
4 Cocaine

78

Atomoxetine

Selective inhibitor of NE reuptake w/ mostly CNS effects (maybe inc. in BP)

Used to treat ADHD

79

Subutramine

Serotonin and NE reuptake inhibitor

Appetite suppressant, but taken off the market recently b/c of negative CV effects

80

Doluxetine

Serotonin and NE reuptake inhibitor

Antidepressant

81

Cocaine

Inhibits peripheral reuptake of NE

In CNS, has amphetamine-like actions, more intense.

Inhibition of DA reuptake in pleasure center of brain --> leads to rapid addiction

82

What would be used to treat a patient w/ hypotension?

Goal: Raise BP

Use alpha 1 agonists such as NE, phenylephrine

83

What would you use to treat a patient in shock?

Positive inotropic agents such as dopamine and dobutamine

84

What would you use to treat a patient w/ hypertension?

an alpha 2 agonist such as clonidine

85

What would you use to treat orthostatic hypotension?

Alpha 1 agonist like midodrine

86

What would you use in emergency cardiac measures?

Epinephrine
Isoproterenol

87

What are the two goals of surgical use of sympathomimetics?

1. Reduce blood loss at site of surgical manipulations

2. Slow diffusion of anesthetics away from site of administration

88

What drugs are used to reduce blood loss at site of surgical manipulations?

Epi or cocaine

89

What drugs slow diffusion of anesthetics away from site of administration?

Epi, NE, phenylephrine

90

What drugs are used as a sinus decongestant?

Alpha 1 agonist --> cause vasoconstriction

Phenylephrine and Oxymetazoline (Afrin)
**No more than 3 days of use due to rebound effect!!!

91

How are sympathomimetics used to treat anaphylaxis?

Epi activates alpha 1, beta1, and beta2 receptors to reverse symptoms of anaphylaxis

*Often use steroid or antihistamine in combination

92

What are the 3 ways drugs can treat ophthalmic problems?

1. Alpha 1 agonists cause mydriasis --> useful for eye exam

2. Alpha 1 agonists used as decongestants to reduce red eye

3. Alpha 2 agonists reduce intraocular pressure of glaucoma

93

Three drugs used in the treatment of ADHD

1. Methylphenidate (ritalin)

2. Dextroamphetamine (Adderall)

3. Lisdexamfetamine (Vynase)