Adrenergics (Konorev) Flashcards

1
Q

Direct acting adrenomimetics come in three broad flavors. What are they?

A

Alpha agonists

Mixed alpha and beta agonists

Beta agonists

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2
Q

What are the alpha agonists?

A

Phenylephrine (Neo-Synephrine) (a1>a2>>>B)

Clonidine (Catapres) (a2>a1>>>>B)

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3
Q

What are the mixed alpha and beta agonists?

A

Norepinephrine (Levophed) (a1=a2; B1>>>B2)

Epinephrine (Adrenalin) (a1=a2; B1=B2)

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4
Q

What are the Beta agonists?

A

Dobutamine (Dobutrex) (B1>B2>>>>a)

Isoproterenol (Isuprel) (B1=B2>>>a)

Albuterol (Ventolin) (B2>B1>>>a)

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5
Q

Indirect Adrenomimetics come in four flavors. What are they?

A

Reuptake inhibitors of DA and NE

Inhibitors of MAO

Reverse NE and DA uptake mechanisms and increase release

Releasing agent and direct adrenergic receptor agonist

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6
Q

What are the DA and NE reuptake inhibitors?

A

Cocaine

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7
Q

What are the inhibitors of MAO?

A

Selegiline (Eldepryl)

Phenelzine (Nardil)

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8
Q

What drugs reverse NE and DA uptake mechanisms and increase their release?

A

Amphetmines

Methyphenidate (Ritalin)

Tyramine (not a drug)

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9
Q

What drugs are releasing agents AND direct adrenergic receptor agonists?

A

Ephedrine

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10
Q

What are the two targets of adrenergic drugs?

A

Sympathetic cholinergic terminals at the target site (NE or DA)

Examples: Cardiac and smooth muscle, glands, nerve terminals (NE); renal vascular smooth muscle (DA).

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11
Q

What is the primary role of adrenergic drugs?

A

Modulate adrenergic transmission and primarily control the function of sympathetic nervous system

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12
Q

What is the effect of drugs that activate adrenergic transmission?

A

AKA adrenomimetics or sympathomimetics

These mimic/promote the effects of NE, epinephrine, DA, at adrenergic receptors in the sympathetic NS

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13
Q

What is the effect of drugs that inhibit adrenergic transmission?

A

AKA sympatholytics/antiadrenergics

These prevent the effects of NE/DA/epinephrine at adrenergic receptors in the sympathetic NS

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14
Q

Direct acting adrenergic drugs produce their effects how?

A

By interacting with adrenergic receptors

either: adrenergic receptor agonists or antagonists

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15
Q

Indirect acting adrenergic drugs produce their effects how?

A

By increasing or reducing the concentration of NE at target receptors

This works by altering NTM concentration at the target site

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16
Q

MAO inhibitors, reuptake blockers, and releasing agents all take place where?

A

at the presynaptic neuron (reuptake blockers and MAO inhibitors) and in the synapse (releasing agents)

These are all indirect acting

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17
Q

Adrenergic receptor agonists take place where?

A

At the post synaptic neuron

these are direct acting

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18
Q

What are the effects of epinephrine on cardiac function?

A

Acts on B1

Increases force of contraction (positive inotropic)

increase HR

increases conduction velocity at AV node

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19
Q

What are the effects of Epinephrine on vascular tone?

A

Acts on B2 and a1

increases systolic BP

may decrease diastolic BP and TPVR

MAP unchanged

Note: many different receptor types in vascular beds

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20
Q

What other tissues and receptor types can Epinephrine effect?

A

skin vessels and mucous membranes-mostly a1

skeletal muscle-a1 and B2

renal and cerebral-D1 and a1

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21
Q

What are the effects of epineprhine on the respiratory system?

A

relaces bronchial muscle at B2

decreases secretions and congestion in mucosa at a1

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22
Q

What are the effects of epinephrine on skeletal muscles?

A

causes muscle tremor at B2

increases K uptake at B2

promotes hypokalemia and decreases K excretion by kidney

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23
Q

What are the effects of epinephrine on serum concentrations of glucose/FFA, renin?

A

Enhances liver glycogenolysis and gluconeogenesis (B2)

increases FFA in blood (B)

increases renin release (B1)

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24
Q

What are the effects of NE?

A

a1=a2; B1>>B2

  • stimulates cardiac muscle, reduces HR
  • vasoconstrictor
  • lacks B2 agonist effects, no bronchodilation or vasodilation
  • increases PVR and BP
  • role of baroreflex
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25
What is the role of phenylephrine?
* a agonist, a1\>a2\>\>\>B * effective mydriatic and decongestant * severe vasoconstriction, BP elevation and severe bradycardia * baroreflex in response to phenylephrine
26
What are the effects of Clonidine?
* Selective a2 agonist, \>a1\>\>\>\>B * central effect on presynaptic a2 receptors in lower brainstem * decreases sympathetic outflow * reduces BP * bradycardia * locally-produces vasoconstriction
27
What are the effects of Isopreterenol?
* B1=B2\>\>\>a * non-selective beta agonist * positive inotropic and chronotropic action, increases CO (B1) * vasodilator and decreases arterial pressure (B2) * causes bronchodilation (B2)
28
What are the effects of Dobutamine?
* B1\>B2, a1 * Selective B1 agonist with a1 receptor activity * **negative isomer is an agonist at these receptors while a positive isomer is an a1 antagonist** * potent inotriopic action * less chronotropic action compared to isoproterenol
29
What are the effects of Albuterol?
* B2\>B1\>\>\>a * selective B2 agonist * causes bronchodilation
30
What are some unique features of indirect acting adrenomimetics?
* more lipophilic (not catecholamines) * easily penetrate BBB (but not tyramine) * central nervous effects/stimulants * heavily abused drugs (amphetamines, methylhenidate, cocaine)
31
What is tyramine?
* a product of decarboxylation of tyrosin * hydrophilic and doesn't cross BBB * accumulated at high concentrations in certain foods * metabolized by MOA in liver * causes elevation of systolic blood pressure when given IV * Tyramine pressor test is used to evaluate peripheral adrenervic function
32
What drugs are used to treat hypotensive emergencies like hemorrhagic shock, overdose of antihypertensives, or CNS depressants? Chronic hypotension? Cardiogenic shock?
NE, phenylephrine Ephedrine Dobutamine
33
What drugs are used to treat heart failure? HTN? Emergency treatment for complete AV block and cardiac arrest?
short term dobutamine in acute HF a2 agonists for long term treatment Epinephrine, isoproterenol
34
What drugs are used to treat depression? narcolepsy?
Phenelzine, Selegiline Amphetamines, Methylphenidate
35
What drugs are used to treat ADHD? Obesity?
Methylphenidate Ephedrine, Amphetamines
36
What drugs are used to treat bronchial asthma? Congestion? Anaphylaxis?
Albuterol Phenylephrine, ephedrine Epinephrine (resp. and CV components)
37
What drugs are used to treat glaucoma? Examine the retina? Urinary stress incontinence?
a2 selective agonists Phenylephrine-induces mydriasis Ephedrine
38
What are the cardiovascular adverse effects of adrenomimetics?
* increased BP * increased cardiac work leading to MI and HF * Sinus tach. and serious ventricular arrhythmias, inducing sudden cardiac death
39
What are the central nervous system toxities related to indirect acting lipophilic drugs?
* insomnia * lack of apetite * anxiety, restlessness * psychoses * convulsions and hemorrhagic stroke (cocaine)
40
Direct acting antiadrenergic drugs come in three flavors. What are they?
a adrenoceptor antagonists Mixed blockers B adrenoceptor blockers
41
What are the a adrenoceptor antagonists?
**non-selective a1 and a2 receptor antagonists** * Phentolamine (Oraverse) * Phenoxybensamine (Dibenzyline) **a1 receptor selective** * Prazosin (Minipress) * Tamsoluosin (Flomax) * Doxazosin (Cardura)
42
What are the mixed antiadrenergic blockers?
Labetalol (Trandate, B and a1 antagonist) Carvedilol (Coreg, B and a1 antagonist)
43
What are the B adrenoceptor blockers?
**B1 and B2 blockers** * propranolol (inderal) * Pindolol (Visken) * Nadolol (Corgard) **B1 Selective** * Metoprolol (Toprol) * Betaxolol (Kerlone) * Acebutolol (Sectral) * Atenolol (Tenormin)
44
What are the indirect acting antiadrenergic drugs?
NE relase inhibitor: Guanethidine (Ismelin) Tyrosine hydroxylase inhibitor: Metyrosine (Desmer)
45
Where do tyrosine hydroxylase inhibitors act?
at the presynaptic neuron Indirect acting
46
Where do NE release inhibitors function?
At the synapse Indirect acting
47
Where do adrenergic receptor antagonists act?
at the post synaptic neuron Direct Acting
48
Describe the dose response curve of Phentolamine
a reversible competitive a agonist noncovalent binding to a receptor shorter acting effect antagonized by high concentration of agonist
49
Describe the dose response curve to Phenoxybensamine
a non-competitive irreversible a antagonist covalent binding to receptor longer acting not antagonized by alpha agonist
50
What are the cardiovascular effects of alpha antagonists?
* decreased PVR and BP * Postural hypotension * Reflex tachycardia
51
What are the effects of alpha antagonists on the GU system?
Relaxation of smooth muscles in prostate decreased resistance to flow of urine
52
What are the effects of alpha antagonists on the eye?
relaxation of the pupillary dilator muscle-miosis
53
What drugs are used to treat pheochromocytoma?
Phentolamine Phenoxybenzamine metyrosine
54
What drugs are used to treat chronic HTN?
Prazosin Doxazosin **these are a1 selective**; nonselective a blockers are NOT used for this
55
What drugs are used for ED?
combination of phentolamine and a nonspecific vasodilator papaverine (injected into penis)
56
What drugs are used to treat BPH (urinary obstruction)
**Tamsulosin** greater selectivty for the a1A than a1B a1A is the most important a receptor subtype mediating prostate smooth muscle contraction effectively relieves urinary obstruction and pain with little effect on BP prazosin and doxazosin are also effective by drop BP more
57
What are the adverse effects of alpha antagonists?
* fewer with a1 selective antagonists * postural hypotension with antagonism of a1 in venous smooth muscle * nasal stuffiness * tachycardia * retention of fluid and salt * impaired ejaculation
58
Beta blockers: Antagonists
atenolol nadolol propranolol
59
Beta Blockers: Partial agonists
Acebutolol labetolol pindolol
60
Beta blockes: inverse agonists
betaxolol metoprolol
61
What makes a beta blocker a partial agonist?
Beta blockers with Intrinic sympathomimetic activity are partial agonists at beta adrenergic receptors block sympathetic effects but have submaximal effects of their own, causing a blunted sympathetic response less risk for bradycardia, increase in VLDL/HDL, and other effects
62
What are the effects of beta blockers on the heart?
negative inotropic effect negative chronotropic effect slow conduction via AV node
63
What are the effects of beta blockers on the blood vessels
initially-rise in peripheral vascular resistance chronic use-decrease in PVR (lower BP in hypertensive individuals)
64
What are the effects of beta blockers in the RAAS system?
Inhibits renin release
65
What are the effects of beta blockers on the respiratory system?
increase airway resistance
66
What are the effects of beta blockers on the eye?
reduces production of aqueous humor, reduces intraocular pressure
67
What are the metabolic effects of beta blockers?
inhibits lipolysis increases VLDL and decreases HDL, reduces HDL cholesterol/LDL cholesterol ratio inhibits glycogenolysis and gluconeogenesis in the liver
68
How do beta blockers treat HTN?
antihypertensive effect is delayed both beta blockers and mixed a-B blockers are used
69
How are beta blockers used to treat angina pectoris?
blcoking cardiac beta receptors decreases cardiac work and reduces oxygen consumption beta blockers reduce the frequency of anginal episodes and improve exercise tolerance
70
How are beta blockers used to treat MI?
long term use in post-infarction period prolongs survival -propranolol or metoprolol
71
How are beta blockers used to treat cardiac arrhythmias?
effective in ventricular and supraventricular arrhythmias including A. flutter and A. fib and ventricular ectopic beats
72
How are beta blockers used to treat heart failure?
effective for the treatment of chronic heart failure in selected pts. -metoprolol and carvedilol shown in CT to be effective Contraindicated in acute or severe CHF
73
How are beta blockers used to treat glaucoma?
reduces aqueous humor produciton by ciliary body Betaxolol (a blocker w/o local anesthetic activty, don't use propranolol)
74
How are beta blockers used to treat hyperthyroidism?
Propranolol us used to treat excessive catecholamine action on heart, thyroid storm, tachycardia, supraventricular and ventricular ectopic arrhythmias
75
What are the adverse effects of beta blockers on the CNS?
sedation sleep disturbances depression Switch to more hyrophilic drug
76
What are the adverse effects of beta blockers on the respiratory system?
increase airway resistance trigger bronchospasm and asthma attach Switch to b1 selective
77
What are the adverse effects of beta blockers on the cardiovascular system
Depresison of HR, cardiac contractility and excitability switch to partial agonist
78
What are the effects of beta blockers on the lipid profile?
chronic use-increase in VLDL, decrease in HDL and decreased HDL/LDL ratio seen with selective and nonselective B blockers switch to partial agonist drug
79
Describe the adverse effect: hypoglycemic episodes due beta blockers
delays recovery from insulin induced hypoglycemia by inhibiting glucose output by the liver blunts perception of hypoglycemia (no sx) increased incidence and severity in pts with TIDM on insulin safer in TIIDM Switch to B1 selective
80
What happens with abrupt discontinuation of beta blocker therapy?
enhanced cardiac stimulation and arrhythmias increased risk in pt's with ischemic heart disease need to gradually taper dosing to prevent sympathetic hyperresponsiveness and potential toxicity