2010 11 03 Part 2 Adrenergic Agonists And Antagonists

Front 1

Dopamine clinical uses
3X

Back 1

increase CO
supports BP
maintains renal function

Front 2

Dopamine Dosage

Back 2

infuse at a rate of 1-20 mcg/kg/min depending on desired effect as stated above

Front 3

Isoproterenol class

Back 3

Pure Beta Agonist

Beta 1 and Beta 2

Front 4

Isoproterenol clinical uses

Back 4

1. Reverse atropine resistant bradycardia, third degree heart block or excessive blockade

Decrease pulmonary vascular resistance (with pulm htn, mv dz)

Front 5

Isoproterenol not a good inotropic choice
why?

Back 5

myocardial oxygen demand increases while oxygen supply falls

Front 6

Dobutamine class

Back 6

Selective beta-1 agonist

Front 7

Dobutamine 3 points

Back 7

Increases CO

lncreased LV filling pressures

Modest increase in HR (less marked than with other beta agonists)

Front 8

Dobutamine clinical Uses

Back 8

CHF and CAD combination

favorable effects on myocardial oxygen balance, particularly if PVR and HR are already elevated

Front 9

Dobutamine
Dosage:

Back 9

Infuse at rate of 2-20 ug/kg/min

Front 10

Phenylephrine class

Back 10

direct alpha 1 agonist


Synthetic noncatecholamine .

Front 11

Phenylephrine stimulates

Back 11

direct alpha-1 adrenergic receptors

Front 12

Phenylephrine High dose may

Back 12

stimulate alpha-2 and beta receptors
(causing reflex bradycardia)

Front 13

Phenylephrine Mimics effects of

Back 13

Norepinephrine

Front 14

Phenylephrine very helpful with

Back 14

MOA's

Front 15

Phenylephrine Primarily peripheral _

Back 15

vasoconstiction
-Resulting rise in SVR and arterial blood pressure

Front 16

Phenvlephrine

4 cardiovascular effects

Back 16

reflex bradycardia with decreased CO

cornary blood flow falls

decreases renal blood flow

elevates pulmonary artery pressure

Front 17

Phenylephrine
bolus

Back 17

50-200 mcg lV
typical bolus

Front 18

Phenylephrine mixed

Back 18

mix to 1mg / 10ml
or
100mcg/ml

Front 19

Phenylephrine
used to treat 3X

Back 19

Decreased BP that accompanies SNS produced by a regional anesthetic

Peripheral vasodilatation which accompanies administration of injected or inhaled anesthetics

SVT, reflex vagal effects can be used to slow HR

Front 20

Phenvlephrine Continuous infusion

Back 20

20-50 mcg/min

Front 21

Phenylephrine Clinical uses:

Back 21

Sustain BP during cardiopulmonary bypass or during carotid endarterectomy

Front 22

Ephedrine class

Back 22

alpha and beta adrenergic stim

Front 23

Ephedrine Longer acting than Epinephrine blc it is: 4X

Back 23

a noncatecholamine
-Much less potent
-Indirect and direct actions
-Stimulates the CNS

Front 24

Ephedrine does not decrease

Back 24

uterine blood flow

-Unlike direct-acting alpha-1 agonists

Front 25

Ephedrine
n/v

Back 25

Possesses antimetic properties

Particularly that which is associated with hypotension following spinal anesthesia

Front 26

Ephedrine Uses:

Back 26

Temp vasopressor during anesthesia

Front 27

Ephedrine Dosage
-Bolus

(adults) (children)

Back 27

2.5 - 10 mg IV (adults)

0.1 mg/kg IV (children)

Front 28

Ephedrine Subsequent dosing leads to

Back 28

tachyphylaxis

Front 29

Adrenergic Antagonists 3 effects

Back 29

bind to adrenoreceptors but do not activate (change cell function)

prevent activity that would normally occur

Extent of response to receptor blockade depends on degree of existing sympathetic tone

Front 30

Alpha antagonists
effects 4

Back 30

Bind to alpha adrenergic receptors

interferes with catecholamines or other sympathomimetics to provoke alpha-responses

Prevent the effects of catecholamines and sympathomimetics on the heart and peripheral vasculature

Prevents inhibitory action of Epinephrine on insulin secretion
(stim insulin secretion)

Front 31

Alpha antagonists
4 side effects

Back 31

hypotension
reflex tachycardia
impotent
unimpeded beta effects

Front 32

Phentolamine
Mechanism of'action:

Back 32

Competitive alpha adrenergic antagonist
(reversible blockade)

peripheral vasodilation, decline in arterial blood flow

Front 33

.Phenoxybenzamine.
mechanism of action:

Back 33

Binds covalently to produce an irreversible block
(Covalent bond)

Front 34

Phentolamine
onset
Duration:

Back 34

2 minutes

10-15 min

Front 35

which structures are secondarily retroperitoneal?

Back 35

duodenum (except first few cm), ascending colon, descending colon

Front 36

Phentolamine Parasympathetic dominance causes 3x

Back 36

Hyperperistalsis
Abdominal pain ..
Diarrhea

Front 37

Phentolamine Clinical Uses: 1X

Back 37

acute hypertensive emergencies
i.e. (pheo, autonomic hyperreflexia)

Front 38

Phenoxybenzamine class

Back 38

Non-selective alpha antagonist

Front 39

Phenoxybenzamine
binding and metabolism

Back 39

Binds covalently

terminated by metabolism

Front 40

Phenoxybenzamine and epinephrine

Back 40

Prevents Epinephrine from inhibiting insulin secretion
(greater alpha 1 effects)

Front 41

Phenoxybenzamine side effects

Back 41

-Miosis
-Nasal stuffines
-Sedation

Front 42

Phenoxybenzamine
Clinical Uses: 3X

Back 42

-Raynaud's syndrome
-Pheochromocytoma
-Excessive vasoconstriction wI asso~iated tissue ischemia (i.e.) reversing acute hemorragic shock

Front 44

Beta antagonists
2 points class

Back 44

Bind selectively to beta-adrenergic receptors
-Competitive inhibition
-Reversible binding

Front 45

Beta antagonists
3 MOA

Back 45

-Interfere with the ability of catecholamine or other sympathomimeics to provoke beta response

-Prevent effects of catecholamines on the heart, airway an blood vessels

-Most prominent effects on Cv system, but can also effect airway resistance

Front 46

Beta antagonists Cross BBB and placenta producing:

5X

Back 46

fatigue

lethargy

fetal bradycardia

hypotension and hypoglycemia

Front 47

Beta antagonists and epinephrine

Back 47

Alpha effects of epinephrine are accentuated -Because beta-2 vasodilating effects of epinephrine are blocked

Front 48

Beta antagonists and resp

Back 48

Bronchoconstriction
(because they are nonselective)

Front 49

Beta antagonists and K

Back 49

may increase K+ concentrations

Front 50

Beta antagonists
and
Up regulation

2X

Back 50

Chronic administration is associated with an increase in the number of beta-adrenergic receptors.

-Continue throughout perioperative period to maintain desirable effects and avoid the risk of SNS hyperactivity

Front 51

Beta antagonists
Side effects: 6X
(chronic use)

Back 51

- Nausea & vomiting
- Fever
- Rash
- Mypopathy
- Alopecia
- Thrombocytopenia

Front 52

Beta antagonists Clinical Uses: in OR
2X

Back 52

HTN
excessive SNS prevention

Front 53

Beta antagonists
may be classified into

2X

Back 53

Nonselective vs. Selective
beta-1 and beta-2

Partial or pure (presence or absence of intrinsic sympathomimetic activity)

Front 54

Propranolol class

Back 54

nonselective beta 1 and beta 2

Front 55

Propranolol cleared

Back 55

Extensively protein bound
-Cleared by hepatic metabolism

Front 56

Propranolol
BP lowered due to 3 things

Back 56

decreased myocardial contractility
lower heart rate
diminished renin release

Front 57

Propranolol decreases
2 cardiac points

Back 57

Cardiac output and 02 demand of heart are reduced

Front 58

Propranolol clinical Uses: 6X

Back 58

Myocardial lschemia -
LV outllow obstruction
Slows A-V conduction and stabilizes myocardial membranes _ Slows ventricular response to SVT
Thyrotoxicosis
Pheochromocytoma

Front 59

Propranolol side effects
4X

Back 59

bronchospasms
CHF
bradycardia
AV blocks

Front 60

Propranolol -Withdrawal syndrome

Back 60

-Caused by abrupt discontinuation of Propranolol therapy for 24-48 hours

Characterized by HTN, tachycardia and angina

-This effect is caused by upregulation of the beta-receptors

Front 61

Esmolol class

Back 61

selective beta 1 antagonist

Front 62

Esmolol short acting due to

Back 62

rapid redistrubation and hydralysis

Front 63

Esmolol -Elimination half life is

Back 63

9 minutes

Front 64

Esmolol Considered to be cardioselective however

Back 64

-However, at higher doses it inhibits beta-2 receptors in bronchial and vascular smooth muscle

Front 65

Esmolol Clinical Uses:
2 areas of use

Back 65

1. Prevent tachycardia and hypertension in response to perioperative surgical stimuli

intubation
surgical stim
emergence

2. Control ventricular rate in response to atrial fibrillation or flutter

Front 66

Esmolol Dosage:
-Bolus

Back 66

0.2-0.5 mg/kg

Front 67

Esmolol Infusion

Back 67

-Loading dose of 0.5 mg/kg (over 1 minute)

50 mcg/kg/min; for long term therapy
Increase by increments of 50 mcg min, Max of 200 mcg/kg/min

Front 68

Labetalol class

Back 68

alpha 1, beta 1, beta 2

alpha < beta

beta much more effects

Front 69

Labetalol uses 2X

Back 69

hypertension

tachycardia

Front 70

Labetalol side effects
3X

Back 70

LV failure
paradoxical HTN
Bronchospasms