Exam 2: ANS Pharmacology Flashcards Preview

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Flashcards in Exam 2: ANS Pharmacology Deck (143):
1

Organs that are only innervated by SNS:

Sweat glands
Blood vessels (though they have M receptors)

2

Organs only innervated by PSNS:

Ciliary muscle of eye
Bronchial smooth muscle (though they have B2 receptors)

3

Receptors on skeletal muscle:

Nicotinic (Nm)

4

Receptors on blood vessels and other smooth muscle:

Adrenergic (alpha/beta)

5

Receptors on sweat glands:

Muscarinic (M1-5)

6

Receptors on adrenal medulla:

Nicotinic - preganglionic

7

Receptors on salivary glands etc:

Muscarinic

8

How is the adrenal medulla an anomaly?

Acts like a ganglia but releases NE/Epi as hormones

9

Norepi/epi % release:

Norepi 20%
Epi 80%

10

How are the sweat glands an anomaly?

Innervated by the SNS, but postganglionic neuron releases ACh onto a muscarinic ACh receptor

Sympathetic cholinergic!

11

How are the blood vessels an anomaly?

No PSNS innervation, although muscarinic ACh receptors present (require circulating ACh)

12

Name the endogenous catecholamines:

Epi
Norepi
Dopa

ENDogenous

13

Name the synthetic catecholamines:

Isoproterenol
Dobutamine

14

Name the indirect acting synthetic non-catecholamines:

Mephentermine
Ephedrine
Amphetamines

MEA culpa is an INDIRECT way of saying "my bad!"

15

Name the direct acting synthetic non-catecholamines:

Phenylephrine
Methoxamine

Don't comment publicly, just PM me directly...

16

Name the selective α2 agonists:

Clonidine
Dexmedetomidine

17

Name the selective β2 agonists:

Abuterol
Terbutaline
Ritodrine

18

How do direct agonists work?

Either mimic the endogenous substance or directly activate the receptor

19

How do indirect agonists work?

Stimulate release of NTs

20

Structure of all sympathomimetics:

Beta-phenylethylamine derivatives

21

Chain of catecholamine formation:

Tyrosine
DOPA
Dopamine
Norepinephrine
Epinephrine

22

Termination of effect of catecholamines:

Reuptake (I/II)
MAO
COMT
Lungs

23

Termination of effect of non-catecholamines:

MAO
Urinary excretion

24

Reuptake I vs II:

I: Neuronal (80%)
II: Extraneuronal

25

How do MAO inhibitors cause problems with sympathomimetics?

Non-catecholamines are unable to be broken down and have an increased effect

26

Relative receptor activation of α-agonists:

Phenylephrine: α1 > α2
Clonidine: α2 > α1

27

Relative receptor activation of mixed α/β agonists:

Norepi: α1=α2; β1 >>> β2
Epi: α1=α2; β1=β2

Equal Epi
Nonequal Norepi

28

Relative receptor activation of β-agonists:

Dobutamine: β1 > β2
Isoproterenol: β1 = β2
Terbutaline/albuterol: β2 > β1

29

Relative receptor activation of dopamine agonists:

Dopamine: D1 = D2
Fenoldopam: D1 >> D2

30

MoA of epinephrine:

α and β receptor activation
Most potent α receptor activator!

31

PK of epinephrine:

Very poorly lipid soluble (no CNS effect)
IV onset: 1-2 min
Duration: 5-10 min

32

Indications for epinephrine:

Bronchial asthma
Acute allergic rxn
Cardiac arrest/asystole
Vfib unresponsive to defib

33

Resuscitation dose of epinephrine:

10mcg/kg IV

34

Infusion dose of epinephrine:

1-2mcg/min: β2 for bronchospasm
4-5mcg/min: β1 for ↑ contractility
10-20 mcg/min: α (more prominent as dose ↑) and β

35

CV effects of epinephrine:

BP regulation is major role
α1: Vasoconstriction, ↑BP / CVP / work
α2: Negative feedback ↓ BP
β1: ↑ contractility, HR, CO, BP
β2: Peripheral vasodilation ↓ BP

At moderate doses:
SBP increases
DBP decreases
MAP stays the same

36

Cerebral effects of epinephrine:

Minimal vasoconstriction
↑ CBF

37

Ocular effects of epinephrine:

Dilation of pupils/mydriasis (α1)
Increased humoral outflow (α1/α2), production of aquaous humor (β1)

38

Respiratory effects of epinephrine:

Bronchodilation (β2)
Decreased histamine release (β2)
Reduced mucosal secretions (α1)

Good for treating bronchospasm, anaphylaxis

39

GI effects of epinephrine:

Decreased digestive secretions (α2)
Decreased peristalsis (α, β2)
Decreased blood flow (α1)

40

GU effects of epinephrine:

Renal blood flow dramatically reduced! (α1)
Increased renin release (β1)

Contraction of urethral sphincter (α1) and bladder relaxation (β2)

Inhibition of labor (β2)

41

Metabolic effects of epinephrine:

↑ glycogenesis, insulin release (β2) - inhibition of release by α2, but minor

Peri-op pts need *more* insulin than usual

42

Hypotension dosing for norepi:

4-16mcg/min

43

Indications for norepi perioperatively:

Hemorrhage (redistribute remaining blood)
Septic shock last line

44

Effects of norepi:

Intense vasoconstriction (α1 with no β2 to balance!!)
↑ BP activates baroreceptors so ↓ HR

45

Dosing of dopamine:

1-3 mcg/kg/min: D1 receptor dominates
3-10 mcg/kg/min: β1 receptor dominates
> 10 mcg/kg/min: α receptor dominates

46

Effects of dopamine:

↑ contractility, renal BF, UOP, GFR
↑ endogenous norepi release
Inhibition of carotid bodies / altered response to hypoxia
↑ ocular pressure

47

Dopamine and dobutamine:

Synergistic; reduces afterload, improves CO

48

MoA of isoproterenol:

β1 and β2 agonist

49

Effects of isoproterenol:

↑ HR, contractility
↓ SVR means ↑ SBP, ↓ DBP, ↓ MAP

50

Dosing of isoproterenol for block/dysrhythmias:

1-5 mcg/min

51

PK of isoproterenol:

Rapidly metabolized by COMT (need to infuse)

52

Why increased MI risk with isoproterenol?

↑ HR means ↓ O2 delivery to the myocardium

53

Dosing for dobutamine:

2-10 mcg/kg/min

54

Receptors targeted by dobutamine:

β1 selective at < 5 mcg/kg/min
Weak a1 stimulation > 5 mcg/kg/min

55

Effects of dobutamine:

↑ CO without increasing HR/BP
Coronary artery vasodilator

56

MoA of ephedrine:

Indirect agonist at α and β receptors

57

Indications for ephedrine:

Hypotension with bradycardia

58

Dosing for ephedrine:

10-25 mg IV
10-50 mg IM

59

Negative effect of ephedrine:

Tachyphylaxis d/t norepi depletion

60

PK of ephedrine:

Excreted unchanged in urine
Metabolized by MAO and conjugated in liver
Et1/2: 3 hrs

61

MoA of phenylephrine:

Direct α1 agonist

62

Effects of phenylephrine:

Venoconstriction ( > arterial)
↑ BP, SVR
↓ HR, CO

63

Indications for phenylephrine:

Hypotension (not d/t hypovolemia)

64

Dosing for phenylephrine:

50-200 mcg IV
Infusion: 20-50 mcg/min

65

Overdose of phenylephrine or epinephrine:

Give phentolamine (α1 antagonist) or NTG/NTP
NOT a β-blocker, which will ↓ contractility and rate and leave massive vasoconstriction

66

Indications for β2 agonists:

Premature labor, asthma, COPD

67

Side effects of β2 agonists:

Tremor
Reflex tachycardia

68

Indications for albuterol:

Asthmatic bronchospasm

69

Dosing of albuterol:

100mcg/puff
2 puffs q4-6hr

Nebulization: 15mg/hr for 2 hours

70

Side effects of albuterol:

Tachycardia, hypokalemia

71

Indications for terbutaline:

Asthma
Premature labor

72

Difference between salmeterol and albuterol:

Salmeterol duration > 12 hrs

73

Indication for ritordine:

Premature labor

74

Side effects of ritordine:

↑ HR/CO d/t β1 activity
Can cause pulmonary edema

75

MoA and indication for midodrine:

α1 agonist
Postural hypotension

76

Effects of amphetamine:

↑ release of norepi, dopamine, 5HT
Blocks reuptake
Blocks vesicular transport
Inhibits MAO

77

Difference between amphetamine and methamphetamine:

Methamphetamine has higher CNS effects

78

MoA of cocaine:

Prevents reuptake of catecholamines (norepi, dopamine, 5HT)

79

MoA of reserpine:

Vesicles lose ability to store norepi/dopamine/5HT

80

CV effects of α1 antagonism:

Vasodilation ↓ PVR, BP
Postural hypotension

81

CV effects of α2 antagonism:

↑ norepi release by blocking negative feedback

82

GI effects of α-antagonism:

Muscle relaxation and easier urination

83

ENT effects of α-antagonism:

Miosis
Nasal congestion

84

Competitive α-antagonists:

Phentolamine
Prazosin
Yohimbine

85

Covalently binding α-antagonist:

Phenoxybenzamine

86

MoA of phentolamine:

Nonselective α-blocker

87

Effects of phentolamine:

Vasodilation
↓BP
↑HR, CO

88

Indications for phentolamine:

Hypertensive emergencies (pheochromocytoma, ANS dysreflexia)
Extravascular infiltration of sympathomimetics

89

Dosing/timing of phentolamine for HTN crisis:

30-70 mcg/kg IV
Onset: 2 min
Duration: 10-15 min

90

Dosing of phentolamine for extravasation:

2.5 - 5mg in 10ml NS

91

MoA of phenoxybenzamine:

Binds covalently to α1 receptors

92

Effects of phenoxybenzamine:

↓ SVR, vasodilation

93

PK of phenoxybenzamine:

Pro-drug
Onset: 1hr
Et1/2: 24 hrs

94

Indications for phenoxybenzamine:

Pheochromocytoma
Raynaud's disease

95

MoA of prazosin:

Selective α1 antagonist

96

MoA of yohimbine:

Selective α2 antagonist

97

Indications for yohimbine:

Orthostatic hypotension
Impotence

98

MoA and indications for terazosin and tamulosin:

α1 antagonists for BPH

99

Effects of β antagonists:

Improve O2 supply/demand
Can provoke bronchospasm
Vasoconstriction in skeletal muscles
↓ renin release
↓ insulin release

100

MoA of β antagonists:

Competitive and reversible inhibition of β receptors

101

Chronic use of β antagonists:

Upregulation in receptors
*MUST* take β-blocker on DOS or ↑ risk of intra-op MI

102

Non-selective β antagonists:

Propranolol
Nadalol
Timolol
Pindolol

Not Too Particularly Picky

103

Cardioselective/β1 antagonists:

Metoprolol
Atenolol
Acebutolol
Betaxolol
Esmolol

MAABE they're block your receptor, but they're selective

104

Receptor activity of propranolol:

β1 = β2

105

MoA of propranolol:

Lacks sympathomimetic activity; pure antagonist

106

CV effects of propranolol:

↓ HR, contractility, CO
Especially during exercise

↑ PVR, coronary VR

O2 demand lowered

Sodium retention d/t ↓ renin

107

PK of propranolol:

Significant first pass effect
Highly protein bound (90-95%)
Metabolized in liver
Et1/2: 2-3 hrs
↓ clearance of amide LAs
↓ pulmonary first pass effect of Fentanyl

108

Indications for timolol:

Glaucoma

109

Indications for nadolol:

Long-term tx; preferred d/t daily dosing

Et1/2: 20-40 hrs!

110

MoA of metoprolol:

Selective β1 antagonist

111

Effects of metoprolol:

Prevents inotropy, chronotropy

112

PK of metoprolol:

60% first pass effect
Et1/2: 3-4 hrs

113

Dosing of metoprolol:

1-15 mg (1mg at a time)

114

MoA of atenolol:

Most selective β1 antagonist with the least CNS effects

115

PK of atenolol:

Not metabolized in liver; excreted via renal system (VERY polar)
Et1/2: 6-7 hrs

116

Indications for atenolol:

Cardiac patients with CAD

117

MoA of betaxolol:

Selective β1 antagonist

118

Et1/2 and indications for betaxolol:

Et1/2: 11-22 hrs
Daily dose for HTN
Topical for glaucoma with less bronchospastic risk

119

MoA of esmolol:

Selective β1 antagonist

120

PK of esmolol:

Rapid onset
Et1/2: 9 min
Short duration (< 15 min)
Hydrolyzed by plasma esterases

121

Indications for esmolol:

Controlled hypotension
Tourniquet pain
Short noxious stimuli
Wakeups

122

Dosing for esmolol:

0.5 mg/kg IV

Infusion: 50-300 mcg/min

123

Side effects of β blockers:

↓ HR, contractility, BP
Exacerbation of PVD
Bronchospasm
Inhibit uptake of K+ into muscles
↓ BP with inhaled agents
Fatigue, lethargy
N/V/D

124

Relative contraindications for β blockers:

Heart block or cardiac failure
Asthma
DM w/o BG monitoring
Hypovolemia

125

Indications for β blockers:

HTN
Angina
Post-MI
Tachyarrythmias
↓ SNS tone

126

MoA of labetalol:

α1, β1, β2 antagonist
β blockade 7x higher

127

PK of labetalol:

Conjugation metabolism
Very little in the urine
Et1/2: 5-8 hrs

128

Effects of labetalol:

↓ BP, SVR, HR - maximum drop 5-10 mins after administration

129

Dose of labetalol:

0.1 - 0.5 mg/kg

Usually 5mg/time for HTN in OR

130

Side effects of labetalol:

Orthostatic hypotension
Bronchospasm
Heart block
CHF
Bradycardia

131

Which muscarinic receptor most affects the heart?

M2

132

MoA of antimuscarinics:

Competitively, reversibly antagonize ACh at muscarinic receptors

133

Tertiary amines vs. quaternary ammonium antimuscarinics:

Tertiaries: atropine, scopolamine
Quaternary: glycopyrrolate

Tertiary will cross BBB, quarternary will not

134

PK of IV atropine:

Onset 1 minute
Duration 30-60 min
Et1/2: 2.3 hours
18% unchanged, rest hydrolysed

135

PK of IV glycopyrrolate:

Onset 2-3 min
Duration 30-60 min
Et1/2: 1.25 hrs
80% unchanged via urine

136

PK of scopolamine:

Extensively metabolized

137

Indications for antimuscarinics:

Antisialogogue
Sedation
PONV prevention
Bradycardia
Reversal of NMB (with anticholinesterase)
Amnesia promotion in unstable pts
Bronchodilation
Mydriasis
Reduce biliary/ureteral spasm

138

Dosing for ipratropium:

40-80 mcg/puff
2 puffs

0.25 - 0.5 mg via nebulizer

Not fast onset - 30-90 min

139

Scopolamine dosing:

Pre-op: 0.3 - 0.5 mg
1.5 mg transdermal for 72 hours' N/V prevent

140

Atropine dosing:

0.2 - 0.4 mg IV pre-op
0.4 - 1.0 mg IV for bradycardia
2 mg in 5ml NS nebulized for bronchodilation

141

Glycopyrrolate dosing:

0.1 - 0.2 mg IV pre-op or bradycardia

142

S/s of central anticholinergic syndrome:

Restlessness
Hallucinations
Somnolence
Unconsciousness
Delayed emergence

143

Tx for central anticholinergic syndrome:

Physostigmine (anticholinesterase) 15-60 mg/kg IV PRN q1-2hrs