Adrenergic Antagonists Flashcards

1
Q

What is a synonym for adrenergic antagonists?

A

sympatholytics

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2
Q

What are the 2 broad classes of alpha-receptor antagonists?

A

Reversible

Irreversible

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3
Q

Who do alpha-receptor reversible antagonists compete with?

A

agonists

endogenous catecholamines

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4
Q

Describe the mechanism of alpha-receptor reversible antagonists

A

block receptor and dissociate if agonist is present in high enough concentration

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5
Q

What is a alpha-receptor reversible antagonist duration of action dependent on?

A

drug’s affinity for receptor

1/2 life of drug in the body

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6
Q

How do alpha-receptor irreversible antagonists bind?

A

form covalent bonds = permanent block

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7
Q

What is the alpha-receptor irreversible antagonist duration of action dependent on?

A

dependent on synthesis of new receptors (up to several days)

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8
Q

What do alpha-antagonists do in the cardiovascular system?

A

block alpha1-mediated vasoconstriction –> vasodilation –> decrease in peripheral vascular resistance and decrease in BP

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9
Q

What is a side effect of alpha-antagonists in the cardiovascular system?

A

orthostatic hypotension (body’s ability to adjust peripheral vascular resistance has been blocked

reflex tachycardia (response to maintain cardiac output; compensatory mechanism to drop in BP)

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10
Q

What are some other effects of alpha1 antagonists?

A

block mydriasis –> mitosis

block nasal vasoconstriction –> sinus congestion

block alpha-mediated urinary retention –> facilitates urination

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11
Q

What is phenoxybenzamine and what does it do?

A

alpha antagonist

irreversible blockade of alpha1 receptors (more so than alpha2 receptors)

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12
Q

What is the effect of phenoxybezamine?

A

blocks vasoconstriction –> vasodilation

also blocks presynaptic alpha2 receptors (blocks reuptake of norepinephrine (not as potent an effect))

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13
Q

What is phenoxybezamine used to treat?

A

conditions of excessive catecholamine release –> pheochromocytoma (adrenal gland tumor)

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14
Q

What are the symptoms of pheochromocytoma that are treated by phenoxybezamine?

A

over secretion of norepinephrine and epinephrine –> hypertension, headaches, palpitations, sweating

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15
Q

What is phentolamine?

A

reversible blockade of alpha1 receptors and presynaptic alpha2 receptors

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16
Q

What is the effect of phentolamine?

A

alpha1 blocking = decrease peripheral vascular resistance

alpha2 blocking due to increase in cardiac stimulation –> increase HR increase cardiac workload, potential for arrhythmias (due to increase norepinephrine activity b/c blocked norepinephrine reuptake)

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17
Q

What is phentolamine used for?

A

management of pheochromocytoma

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18
Q

What are some other examples of alpha1 antagonists?

A

Prazosin

Terazosin

Doxazosin

Tamsulosin

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19
Q

What is a side effect of prazosin?

A

orthostatic hypertension

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20
Q

What is tamsulosin used for?

A

enlarged prostate

HTN

BPH

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21
Q

What is the effect of tamsulosin?

A

relaxation of arterial/venous smooth muscle –> HTN

relax smooth muscle in prostate (most selective for this)

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22
Q

Some drugs have alpha1 antagonistic as a secondary mechanism of action, in these drugs what is the side effect that you’ll most likely see?

A

hypotension

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23
Q

What are some examples of drugs that have alpha1 antagonistic side effects and what are they usually used for?

A

Haloperidol = antipsychotic

Chlorpromazine = antipsychotic

Trazodone = sleep aid and antidepressant

Ergotamine and dihydroergotamine = migranes

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24
Q

How do beta-receptor antagonists bind to their receptors?

A

Reversibly

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25
Q

Are beta-receptor antagonists pure antagonists?

A

Most are, however some do have some beta-agonist activity (but usually only w/ low concentrations of endogenous catecholamines)

some have local anesthetic properties

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26
Q

Can beta-receptor antagonists be selective?

A

Yeah, differ in affinity and selectivity for blocking beta1 or beta2

However, selectivity will decrease w/ higher doses

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27
Q

Are there pharmacokinetic differences between beta-receptor antagonists?

A

Yeah, differences between distribution, 1/2 life, and elimination route

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28
Q

What are beta antagonists usually called in the cardiovascular system?

A

Beta blockers

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29
Q

What are beta antagonists used for in the cardiovascular system?

A

control high BP

angina

CHF

MI

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30
Q

What is the mechanism of action of beta-antagonists in the control of high BP?

A

complex and unclear mechanism

suppression of renin release

CNS actions

debatable first-line agent for high BP

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31
Q

What is the mechanism of action of beta antagonists in the control of angina, CHF, MI?

A

part of first-line therapy

reduce cardiac workload (negative inotropic, negative chronotropic effects)

slow AV node conduction –> decrease HR

suppress renin release

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32
Q

What is the net effect of beta-antagonists in the treatment of angina, CHF, or MI?

A

reduce peripheral vascular resistance, BP, overall workload of the heart

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33
Q

Why is it surprising that beta-antagonists (or blockers) decreases BP?

A

block peripheral Beta2 receptors –> expect inhibit vasodilation BUT w/ long term use BP decreases (unclear mechanism)

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34
Q

What can enhance vasodilation properties of beta antagonists?

A

drugs that also block alpha1 receptors

nonselective agents –> greater drop in BP b/c block vasoconstriction

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35
Q

What is an example of a nonselective adrenergic antagonist that is used to treat high BP?

A

labetolol –> blocks alpha and beta; blocks vasoconstriction

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36
Q

Why are beta antagonists used to treat angina?

A

help pts by improving balance between oxygen supply and demand

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37
Q

Describe the mechanism of beta blockers when treating angina

A

block adrenergic effects of sympathetic nervous system –> reduce cardiac workload –> reduce demand of oxygen

improves exercise tolerance by preventing heart from working to hard

38
Q

Why are beta antagonists contraindicated for use in pts w/ asthma and COPD?

A

No pure beta1 blockers available –> inadvertently block beta2 receptors (which facilitate bronchodilation)

39
Q

Which class of drugs would you want to use to treat COPD and asthma instead of beta antagonists?

A

Beta agonists

40
Q

Which opthalmic disease are beta blockers used to treat?

A

open-angle glaucoma –> reduce production of aqueous humor –> reduce intraocular pressure

41
Q

What are some examples of beta blockers that are used to treat glaucoma and how are they given?

A

Eye drops

Betaxolol

Timolol

Carteolol

Levobunolol

42
Q

What are some side effects of beta blockers?

A

block glucose mobilization

worsen high cholesterol

intrinsic sympathomimetic activity

local anesthetic activity

43
Q

What does it mean to block glucose mobilization?

A

reduce energy availability

inhibit sympathetic-mediated stimulation of lipolysis

partial inhibitor of glycogenolysis –> block body’s availability to make glucose when needed (hypoglycemia)

44
Q

Why would you want to use caution with beta blockers use in an insulin dependent diabetics?

A

beta blockers mask symptoms of hypoglycemia –> pts won’t know when sugars drop

Hypoglycemic symptoms= tachycardia/sweating

45
Q

What are some of the cholesterol issues caused by beta blockers?

A

some types of stored cholesterol levels are altered –> increase cardiovascular risk and coronary artery disease

increase VLDL (very low density lipoproteins aka bad kind)

decrease HDL (high density lipoproteins aka good kind)

46
Q

Which types of beta blockers can cause cholesterol issues?

A

Both selective and nonselective beta blockers

47
Q

Which types of beta blockers have intrinsic sympathomimetic activity (ISA)?

A

beta blocker that has partial beta agonist activity (structural thing)

48
Q

What is a good thing about about intrinsic sympathomimetic activity?

A

may decrease negative features of beta blockers –> i.e. bronchoconstriction and bradycardia

49
Q

What is a bad thing about intrinsic sympathomimetic activity?

A

may reduce the therapeutic effects of beta blockers –> especially cardioprotective benefits

50
Q

What are 3 examples of beta blockers with intrinsic sympathomimetic activity?

A

Labetolol

Pindolol

Acebutolol

51
Q

What is another term for local anesthetic action of beta blockers?

A

membrane stabilization

52
Q

What is the mechanism of local anesthetic action of beta blockers?

A

blockade of Na+ channels in axon of nerves –> prevent electrolytic excitation of the nerve/depolarization/transfer of sensation info

53
Q

What are some examples of beta blockers with local anesthetic action?

A

Acebutolol

Labetolol

Pindolol

Propranolol

54
Q

What are the 7 major uses of beta blockers?

A

Hypertension

Ischemic heart disease

Arrhythmias

Heart failure

Glaucoma

Migrane headaches

Performance anxiety

55
Q

When are beta blockers considered a first line option in treating hypertension?

A

in patients w/ compelling indications (comorbidities)

56
Q

What are the comorbidities that indicate use of beta blockers in treatment of hypertension?

A

Heart Failure

post-MI

Angina

Diabetes

among others

57
Q

What are considered the most important beta blockers used for hypertension?

A

Atenolol

Metoprolol

58
Q

Name the other beta blockers used for hypertension?

A

Bisoprolol

Nadolol

Pindolol

Plus others

59
Q

Would you use beta blockers to treat hypertension if a patient didn’t have the comorbidities?

A

No –> beta blockers aren’t considered first line for these patients

60
Q

What causes ischemic heart disease?

A

cholesterol plaques in cardiac arteries–> decrease blood flow and oxygen delivery

61
Q

What types of symptoms would pts with ischemic heart disease have?

A

Angina

Poor exercise tolerance

62
Q

What are the effects of beta blockers in patients with ischemic heart disease?

A

decrease cardiac workload (slow HR, decrease strength of heart squeeze) –> less demand for O2 (limited supply meets less demand)

63
Q

When are beta blockers considered first line to treat ischemic heart disease?

A

pts @ risk or after MI

history of angina

history of left ventricular dysfunction

64
Q

What are the 2 beta blockers used to treat ischemic heart disease?

A

propranolol

metoprolol

65
Q

What is an arrhythmia?

A

abnormal electrical rhythm w/in the heart muscle

decrease heart functionality

can be fatal

66
Q

What types of arrythmias are beta blockers used to treat?

A

supra-ventricular arrhythmias

ventricular arrhythmias

atrial fibrillation

atrial fluttering

67
Q

What are the physiologic effects of beta blockers that are useful in the treatment of arrhythmias?

A

extend the resting period of AV nodal cells

slow ventricular response to electrical stimulation –> stop abnormal rhythm (hopefully)

68
Q

Are beta blockers the first line treatment of arrhythmias?

A

No, usually used after other meds have failed

69
Q

What are the 2 beta blockers that are used to treat arrythmias?

A

metoprolol

sotalol

70
Q

Which type of heart failure are beta blockers used for?

A

CHRONIC heart failure

71
Q

What are some examples of beta blockers that are used to treat chronic heart failure?

A

metoprolol

bisprolol

carvedilol

72
Q

What type of eye disease are beta blockers used to treat?

A

Glaucoma

73
Q

What is the method of administration of beta blockers when treating glaucoma?

A

administered directly to the eye

74
Q

What are the effects of beta blocks in the eye (aka why are they used to treat glaucoma)?

A

inhibits the production of aqueous humor

75
Q

What are some examples of beta blockers that are used to treat glaucoma?

A

Timolol

Betaxolol

Carteolol

Levobunolol

76
Q

What are some of the side effects of beta blockers that are used to treat glaucoma?

A

cardiac/pulmonary effects –> systemic absorption

77
Q

What is hyperthyroidism (very general), and what can it lead to?

A

overactive thyroid

lead to excessive catecholamine action –> tachycardia

78
Q

What are the effects of beta blockers that are useful in treating hyperthyroidism?

A

decrease symptoms by blocking adrenergic receptors

decrease conversion of thyroxine (T4) –> triiodothyronine (T3) (t3 = active thyroid hormone)

79
Q

What is an example of a beta blocker that is used to treat hyperthyroidism?

A

Propranolol

80
Q

Which beta blockers are used to treat migraine headaches?

A

metoprolol

propranolol

81
Q

How do beta blockers treat migraine headaches?

A

reduce frequency and/or intensity

82
Q

What is a synonym of performance anxiety?

A

stage fright

83
Q

How do beta blockers treat performance anxiety?

A

eliminate symptoms induced by stress and anxiety:

slow HR

reduce palmar sweating

84
Q

What are some complications of liver disease?

A

cirrhosis

portal vein hypertension

85
Q

What are some effects of beta blockers that are useful in treating hepatic diseases?

A

can have targeted effect to reduce the elevated BP

86
Q

What are 2 beta blockers that are used to treat hepatic disease?

A

Nadolol

Propranolol

87
Q

What are some major side effects of beta blockers?

A

Bradycardia

Worsening of asthma (beta2 in lungs)

worsen cardiac output in pts w/ heart failure

exacerbation of hypoglycemia in diabetics

88
Q

What are some of the minor/less common side effects of beta blockers?

A

mild sedation

vivid dreams

depression

89
Q

Overall why do you want to use caution with the use of beta blockers?

A

the response of pts to beta blockers can be unpredictable

90
Q

What is the most important thing about stopping the use of beta blockers?

A

NEED TO TAPER PTS OFF BETA BLOCKERS

91
Q

Why do you need to taper pts off of beta blockers?

A

abrupt discontinuation can lead to rebound hypertension (esp. in pts being treated for ischemic heart disease or hypertension)

92
Q

What needs to be considered when choosing a beta blocker?

A

Safety issues (side effects)

Partial agonist activity

local anesthetic properties (not a huge concern)

differences in renal/hepatic metabolism

differences in elimination half-life