Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Apex > Unit 4 Pharmacology: IV Anesthetics > Flashcards

Unit 4 Pharmacology: IV Anesthetics Flashcards

1
Q

What is the chemical name of propofol?

A

2,6-diisopropylphenol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the drug class of propofol?

A

Isopropylphenol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the formulation of propofol?

A

1% oil in water

  • soybean oil 10%
  • glycerol 2.25%
  • egg lecithin (yolk) 1.2%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the pKa of propofol?

A

11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What preservatives are used in propofol?

A

Diprivan : disodium edetate (EDTA)

Generics: metabisulfate OR benzyl alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What side effect can be caused by the preservative EDTA in propofol?

A

None, it is not an irritant to the bronchi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What side effect can occur from the preservative metabisulfate in propofol?

A

Can cause bronchospasm in patients with asthma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What side effect can occur from the additive benzyl alcohol in propofol?

A

In infants the benzyl alcohol can accumulate in the brain because they can break it down, but they can not conjugate it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the MOA of propofol?

A

Direct GABA-A agonist

  • increases Cl- conductance
  • leads to neuronal hyperpolarization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the adult induction dose of propofol?

A

1-2 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the adult infusion rate of propofol?

A

25-200 mcg/kg/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the induction dose that should be used for the elderly, debilitated or hypokalemic patient?

A

1-1.5 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the onset of propofol?

A

30-60 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the duration of propofol?

A

5-10 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When does brain concentration of propofol peak?

A

~ 1 min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What causes reawakening with propofol use?

A

Redistribution out of the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Propofol context sensitivity?

A

Pretty insensitive

XX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Clearance of propofol is by?

A

Liver : P450
-clearance exceeds liver blood flow

Extrahepatic metabolism : lungs (mostly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Propofol alpha 1/2 time? Beta 1/2 life?

A

Alpha 1/2 time : 2-8 minutes

Beta 1/2 life : 1-2 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Does propofol have an active metabolite?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the pKa of propofol?

A

11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Is propofol an acid or base?

A

Weak acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Propofol protein binding?

A

98%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Is propofol more ionized or non-ionized (with normal physiologic pH)?

A

More non-ionized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How long in an open bottle of propofol okay to use? Propofol in a syringe?

A

12 hours

6 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Does propofol cross the placenta?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Cardiovascular effects of propofol:

A

Decreased BP due to decreased tone and vasodilation
Decreased SVR
Decreased venous tone -> decreased preload
Decreased myocardial contractility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Why does propofol decrease BP?

A

Decreased SNS and vasodilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

In what patients is the decrease in BP from propofol greater?

A

Geriatric patients

LV dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why does CO decrease with propofol?

A 
Decreases contractility (negative inotrope)
Decreases venous tone which decreases preload
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Why does propofol cause respiratory depression?

A

It shifts the CO2 response curve down and right (less sensitive to CO2)
Inhibits hypoxic ventilatory drive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Does propofol cause bronchodilation?

A

No/maybe

Per Nagelhout: 0/⬆️

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

CNS effects of propofol:

A

Decreased cerebral oxygen consumption (CMRO2)
Decreased cerebral blood flow
Decreased intracranial pressure
Decreased intraocular pressure
Anticonvulsant properties
Myoclonus may occur
Few cases of it inducing seizures, but this is very rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How can propofol make cloudy urine?

A

Increased Uris acid excretion - does not suggest renal impairment or infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Why does propofol decrease cerebral perfusion pressure?

A

Due to the decrease in MAP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Does propofol contain antioxidant properties?

A

Yes - free radical scavenging properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is believed to be the cause of propofol infusion syndrome (PRIS)?

A

Propofol contains an increased level of long-chain triglycerides, which impairs oxidative phosphorylation and fatty acid metabolism, this starves cells of oxygen (particularly cardiac and skeletal muscle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Why can propofol cause green urine?

A

From phenol exrection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What rate/dose is a risk factor for PRIS?

A

> 4mg/kg/hr (67mcg/kg/min)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How many days on propofol infusion is a risk factor for PRIS?

A

> 48 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are other risk factors are there for PRIS besides rate and consecutive days infused?

A 
Sepsis - inadequate oxygen delivery
Catecholamine infusions
High dose steroids
Significant cerebral injury
Children (FDA warning decreased occurrence)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Signs and symptoms of PRIS?

A

Acute refractory bradycardia that can lead to asystole AND at least one of the following:

  • metabolic acidosis (base deficit > 10 mmol/L)
  • Rhabdomylosis
  • Enlarged/fatty liver
  • Renal failure
  • HLD
  • lipemia may be an early sign
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What CK results is a high risk for PRIS?

A

> 5,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the treatment for PRIS?

A 
Stop propofol
Maximize gas exchange
Cardiac pacing
PDE inhibitors
Glucagon
ECMO and/or renal replacement therapy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What dose of propofol has an antipruritic effect? Antiemetic?

A

Antipruretic: 10mg - itching caused by opioids and cholestasis
Antiemetic: 10-20 mg - can be used for PONV (infusion 10 mcg/kg/min)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the chemical name of Fospropofol?

A

Phosphono-O-methyl-2-6-diisopropylphenol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the class of Fospropofol?

A

Isopropylphenol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the formulation of fospropofol?

A

Aqueous solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What benefits does the formulation of fospropofol have over propofol?

A

Prevents burning on injection

Doesn’t support microbial growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the MOA of fospropofol?

A

It is a prodrug

It is metabolized by alkaline phosphatase into propofol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is the induction dose of fospropofol?

A

6.5 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the repeat dose for fospropofol? How often can it be re-dosed?

A

1.6 mg/kg

Not more than every 4 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the onset of fospropofol?

A

5 - 13 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the duration of fospropofol?

A

15 - 45 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How is fospropofol cleared?

A

Since it is metabolized to propofol, the same as it.

Liver P450 enzymes plus extra hepatic metabolism (mostly lungs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Does fospropofol have an active metabolite?

A

Fospropofol is a prodrug, and propofol is the active metabolite
The formaldehyde is metabolized to formate and excreted in the urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is a “nasty” side effect of fospropofol?

A

Genital and anal burning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What is the chemical name of ketamine?

A

2-(o-Chloropheyl)-2 (methylamino) cyclohexanone hydrochloride

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What class is ketamine?

A

Arylcyclohexylamine - a phencyclidine derivative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is the formulation of ketamine?

A

Aqueous solution

It is a racemic mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is the pKa of ketamine?

A

7.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What is the MOA of ketamine?

A

NMDA receptor antagonist - antagonizes glutamate

Secondary receptors: opioid, MAO, serotonin, ME, muscarinic, Na+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What dissociative effect does ketamine have?

A

It dissociates the thalamus (sensory) from the limbic system (awareness)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q 
IV doses for Ketamine:
Induction
Maintenance
Infusion
Analgesia
A

Induction: 1 -2 mg/kg
Maintenance: 1 - 3 mg/min
Infusion: 1 - 3 mcg/kg/min (opioid sparing)
Analgesia: 0.1 - 0.5 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is the IM dose for ketamine?

A

4 - 8 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is the PO dose for ketamine?

A

10 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What is the onsets for ketamine?
IV
IM
PO

A

IV: 30 - 60 sec
IM: 2 - 4 minutes
PO: variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What is the duration of ketamine?

A

10-20 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

How is ketamine cleared?

A

Liver P450

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Does ketamine have an active metabolite?

A

Norketamine

It is 1/3 - 1/5 the potency of ketamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

How is ketamine excreted?

A

Renal excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What are the CV effects of ketamine?

A 
Increases SNS tone
Increases CO
Increases HR
Increases SVR
Increases pulmonary vascular resistance - caution with severe RV failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What can you do if you want to use ketamine without activating the SNS?

A

Use subhypnotic dose - <0.5 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What happens if ketamine is given to a patient with depleted cathecholamine stores (like sepsis or sympathetomy)

A

Ketamine is actually a myocardial depressant, with an intact SNS one will see the expected CV effects of ketamine. Without an intact SNS the myocardial depressant effects will be unmasked.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What are the respiratory effects of ketamine?

A

Bronchodilation
Upper airway muscle tone and airway reflexes remain intact
Maintains respiratory drive (brief period of apnea can occur)
Does not significantly shift the CO2 response curve
Increased oral and pulmonary secretions - Glyco helps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What are the CNS effects of ketamine?

A 
Increased CMRO2
Increased cerebral blood flow
Increased intracranial pressure
Increased intraocular pressure
Increased EEG activity - caution if Hx of seizures 
Nystagmus - caution with ocular sx
Emergence delirium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

How does emergence delirium from ketamine present, and how does the risk last?

A

Nightmares and hallucinations

Risk persists for up to 24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What can you give to help prevent emergence delirium from ketamine? What works best?

A

Benzodiazepine

Midazolam is better than diazepam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What are 4 risk factors for emergence delirium from ketamine?

A

Age > 15 yrs
Female
Dose > 2mg/kg
Hx of personality disorder

79
Q

What type of pain does ketamine relieve better?

A

Somatic > visceral pain

80
Q

How does ketamine stop wind-up pain?

A

Blocks central sensitization and wind-up in the dorsal horn

81
Q

What opioid side effect can ketamine prevent?

A

Hyperalgesia

82
Q

Chronic ketamine can cause:

A

Ulcerative cystitis

83
Q

What IV anesthetic undergoes the least amount of protein binding? How much?

A

Ketamine - 12%

84
Q

What is the chemical name for Etomidate?

A

R-1-methyl-1-(a-methylbenzyl) imidazole-5-carboxylate

85
Q

What class is Etomidate?

86
Q

What affect does pH have on Etomidate?

A

In an acidic pH -> imidazole ring opens -> increased water solubility
In physiologic pH -> imidazole ring closes -> increases lipid solubility

87
Q

What is the plasma protein binding % for Etomidate?

88
Q

What is the MOA of Etomidate?

A

GABA-A agonist

89
Q

What is the induction dose for Etomidate?

A

0.2-0.4 mg/kg

90
Q

What is the onset of Etomidate?

A

30 - 60 seconds

91
Q

What is the duration of Etomidate?

A

5 - 15 minutes

92
Q

How is Etomidate cleared?

A

Hepatic P450 enzymes plus plasma esterases

93
Q

What causes the rapid awakening with Etomidate?

A

Redistribution NOT metabolism

94
Q

Does Etomidate have an active metabolite?

95
Q

What are the CV effects of Etomidate?

A

Minimal changes in HR, SV, or CO

SVR decreases which accounts for small reduction in BP

96
Q

Does Etomidate block the SNS response to laryngoscopy?

97
Q

What are the respiratory effects of Etomidate?

A

Mild respiratory depression (less than propofol and barbiturates)

98
Q

What are the CNS effects of Etomidate?

A

Decreased CMRO2
Decreased cerebral blood flow - cerebral vasoconstriction
Decreased intracranial pressure
Cerebral perfusion pressure remains stable

99
Q

Define myoclonus

A

Involuntary skeletal muscle contractions, dystopia, or tremors

100
Q

What is likely the cause of myoclonus with Etomidate?

A

An imbalance between excitatory and inhibitory pathways in the thalamocortical tract

101
Q

Can Etomidate increase risk of seizure?

A

Etomidate can increase epileptiform (seizure-like) activity and possibly increase the risk for a seizure IF patient has a history of seizures

102
Q

Which anesthetic agent increases mortality in patients with Addisonian crisis?

103
Q

How does Etomidate causes adrenocortical suppression?

A

It inhibits 11-beta-hydroxylase and 17-alpha-hydroxylase

-cortisol and aldosterone synthesis are dependent on the enzyme 11-beta-hydroxylase

104
Q

How long does a single dose of Etomidate suppress adrenocortical function?

A

5 - 8 hours (some books say up to 24 hours)

105
Q

Due to the cause of adrenocortical suppression, in which patients should Etomidate be avoided?

A

Those reliant on the intrinsic stress response - sepsis or acute adrenal failure, they need all the cortisol they can muster

106
Q

What side effect is more common with Etomidate than any other induction agent?

A

PONV (may be as high as 30-40%)

107
Q

Barbiturates are derived from?

A

Barbiturates acid

108
Q

How are the different types of barbiturates made, by doing what to the 6 carbon ring of barbiturate acid? What are they?

A

Thiobarbiturates: sulfur molecule in the second position (increases lipid solubility and potency)
Oxybarbiturates: oxygen molecule in the second position
Others:
-methyl group on the nitrogen lowers seizure threshold and increases potency (methohexital)
-phenyl group at the 5 carbon in cereals the anticonvulsant effect (phenobarbital)

109
Q

What is the chemical name for Thiopental?

A

5-ethyl-5-(1-methylbutyl)-2-thiobarbituric acid

110
Q

What is the formulation of Thiopental?

A

Water soluble

111
Q

What is the pH of Thiopental? What benefit does this have?

A

9 - highly alkaline

No venous irritation or pain on injection

112
Q

What is the MOA of Thiopental? What is the difference between a low/normal dose and high dose?

A

GABA-A agonist - depresses the reticular activating system in the brainstem.
Low/normal dose: increases the affinity of GABA for its binding site
High dose: directly stimulates the GABA-A receptor

113
Q

What is the dose of Thiopental for adults? Children?

A

Adults: 2.5 - 5 mg/kg
Kids: 5 - 6 mg/kg

114
Q

What is the onset of Thiopental?

A

30 - 60 seconds

115
Q

What is the duration of Thiopental?

A

5 - 10 minutes

116
Q

How is Thiopental cleared?

A

Liver P450 enzymes

117
Q

How is rapid wake up from Thiopental explained?

A

Redistribution NOT metabolism

118
Q

What occurs with repeat dosing of Thiopental?

A

Tissue accumulation -> prolong wake up time + hang over effect

119
Q

Does Thiopental have an active metabolite?

A

After normal dosing no

After high dose pentobarbital

120
Q

CV effects of Thiopental?

A

Hypotension - primarily the result of venodilation and decreased preload, secondarily myocardial depression
Histamine release -> hypotension, but short-lived
Baroreceptor reflex is preserved so reflex tachycardia helps to restore CO

121
Q

How does the hypotension caused by Thiopental compare to propofol?

A

Less hypotension than propofol

122
Q

Respiratory effects of Thiopental?

A

Respiratory depression - shift CO2 response curve to the right
Histamine release can cause bronchoconstrition, cause with asthma

123
Q

CNS effects of Thiopental?

A

Decreased CMRO2
Decreased cerebral blood flow - cerebral vasoconstriction
Decreased intracranial pressure - used to tx intracranial HTN
Decreased EEG activity - can cause burst suppression and/or isoelectric EEG
Neuroprotection with focal ischemia but not global ischemia

124
Q

What is Porphyria?

A

Group of diseases in which excessive porphyrins are formed and accumulate in the tissues. It reflects deficiencies in heme synthesis causing painful demyelination of peripheral and cranial nerves.

125
Q

What are the 2 classes of porphyria?

A

Acute - inducible

Chronic - non-inducible or cutaneous

126
Q

What is the most common and dangerous type of inducible porphyria?

A

Acute intermittent porphyria

127
Q

Acute intermittent porphyria is made worse by what 4 things?

A

Stimulation of ALA synthase
Emotional stress
Prolonged NPO status
CYP 450 induction

128
Q

What is the most common sign/symptom of acute intermittent porphyria and which also typically occurs first?

A

Severe abdominal pain

129
Q

What are the signs/symptoms of acute intermittent porphyria?

A

GI: severe abdominal pain, N/V
CNS: anxiety, confusion, seizures, psychosis, coma
PNS: skeletal muscle weakness (risk of respiratory muscle failure), bulbar weakness (risk of aspiration)

130
Q

What drugs should be avoided with porphyria?

A 
Barbiturates
Etomidate
Ketamine
Ketorolac 
Amiodarone
CCB (but not all)
Birth control pills
131
Q

What are 4 important anesthetic management points with porphyria?

A

Liberal hydration
Glucose supplementation (reduces ALA synthase activity)
Heme arginate (reduces ALA synthase activity)
Prevention of hypothermia

132
Q

What common agents are safe to administer with porphyria?

A 
Volatile agents
N2O
NMBs and their reversal agents
Narcotics
Midazolam
Ondansetron
Vasopressors
BB
133
Q

Is regional anesthesia contraindicated with porphyria?

A

No. But most avoid it since it may be difficult to distinguish block-related complications from an acute porphyria attack

134
Q

What happens if Thiopental is injected intra-arterial?

A

Intense vasoconstriction
crystal formation (occludes blood flow)
Inflammation
Tissue necrosis

135
Q

What do you do if Thiopental is injected intra-arterial?

A

Vasodilator: phentolamine or pheoxybenzamine
Sympathectomy: Stellate ganglion block or brachial plexus block

136
Q

What IV agent is the gold standard for electroconvulsive therapy?

A

Methohexital

137
Q

What is the induction dose for Methohexital?

A

1 - 1.5 mg/kg

138
Q

All barbiturates are metabolized by what? Except for which one?

A

Liver P450 enzymes

Phenobarbital - excreted unchanged in the urine

139
Q

Which anesthetic agent produces sedation that most closely resembles natural sleep?

A

Dexmedetomidine

140
Q

What is the chemical name of dexmedetomidine?

A

(S)-4-[1-(2,3-Dimethylphenyl)ethyl]-1H-imidazole monohydrochloride

141
Q

What class is dexmedetomidine?

142
Q

What is the formulation of dexmedetomidine?

A

Water soluble

143
Q

What is the pKa of dexmedetomidine?

144
Q

What is the plasma protein binding % of dexmedetomidine?

145
Q

What is the MOA of dexmedetomidine?

A

Alpha-2 agonist -> decreases cAMP -> which inhibits the locus coeruleus in the pons (sedation)

146
Q

What is the loading dose of dexmedetomidine? Maintenance infusion?

A

Loading dose: 1 mcg/kg over 10 minutes

Infusion: 0.4 - 0.7 mcg/kg/hr

147
Q

What is the onset of dexmedetomidine?

A

With loading dose 10 - 20 minutes

148
Q

What is the duration of dexmedetomidine?

A

After infusion is stopped 10 - 30 minutes

149
Q

How is dexmedetomidine cleared?

A

Liver P450 enzymes

150
Q

Does dexmedetomidine have an active metabolite?

151
Q

CV effects of dexmedetomidine?

A

Bradycardia

Hypotension

152
Q

Explain what happens in relation to BP when dexmedetomidine is given

A

Rapid administration of dexmedetomidine can cause HTN (alpha-2 stimulation in the vasculature -> vasoconstriction). This direct effect occurs before the centrally mediated reduction in SNS tone. So once the CNS effects kick in, they over power the peripheral effects.

153
Q

Respiratory effects of dexmedetomidine?

A

Does not cause respiratory depression
No change in oxygenation
No change in blood pH
No change in the slope of the CO2 response curve

154
Q

CNS effects of dexmedetomidine?

A

Decreases CBF
No change in CMRO2 - there is uncoupling of CBF and CMRO2
No change in ICP

155
Q

How does dexmedetomidine produce sedation?

A

Sedation is the result of decreased SNS tone and decreased level of arousal

156
Q

Does dexmedetomidine provide amnesia?

A

It does not provide reliable amnesia

157
Q

How does dexmedetomidine produce analgesia?

A

By alpha-2 stimulation in the dorsal horn of the spinal cord - this decreases substance P and glutamate release

158
Q

What effect does dexmedetomidine have on shivering?

A

It impairs thermoregulatory response, so it produces anti shivering effect

159
Q

What effect does dexmedetomidine have on evoked potentials?

A

It does not impair evoked potentials

160
Q

What benefits does dexmedetomidine have for use with kids?

A

It reduces incidence of emergence delirium in kids

The nasal and buccal route have high degree of bioavailability making it useful for preop sedation in kids

161
Q

What is the dose for preop sedation in kids? When should it be given?

A

3 - 4 mcg/kg

1 hour prior to surgery

162
Q

What is the chemical name of midazolam?

A

8-chloro-6-(2-flurophenyl)-1-methyl-4 H-imidazo[1,5-a][1,4]benzodiazepine

163
Q

What class is midazolam?

A

Benzodiazepine

164
Q

What is the formulation of midazolam?

A

Imidazole ring

165
Q

What affect does pH have on midazolam?

A

Acidic pH -> imidazole ring opens -> increases water solubility
Physiologic pH -> imidazole ring closes -> increase lipid solubility

166
Q

What preservatives are used in midazolam?

A

0.01% disodium edetate

1% benzyl alcohol

167
Q

What is the MOA of midazolam?

A

GABA-A agonist -> increases frequency of channel opening -> neuronal hyperpolarization

168
Q

How are benzodiazepines different from other GABA-A agonists?

A

Most GABA-A agonists increase channel open time

Benzodiazepines increase open frequency

169
Q

What is the IV sedation dose of midazolam?

A

0.01 - 0.1 mg/kg

170
Q

What is the IV induction dose of midazolam?

A

0.1 - 0.4 mg/kg

171
Q

What is the PO sedation in children dose for midazolam?

A

0.5 - 1.0 mg/kg

172
Q

What is the bioavailability of PO midazolam?

A

50% due to significant first pass metabolism

173
Q

What is the onset of midazolam?

A

30 - 60 seconds

174
Q

What is the duration of midazolam?

A

20 - 60 minutes

175
Q

How is midazolam cleared?

A

Liver P450 enzymes

Intestine P450 enzymes

176
Q

Does midazolam have an active metabolite?

A

1-hydroxmidazolam

177
Q

What is the potency of 1-hydroxymidazolam?

A

0.5 x potency of midazolam and is rapidly conjugated into an inactive compound

178
Q

What condition prolongs the effect of 1-hydroxymidazolam?

A

Renal failure

179
Q

CV effects of midazolam?

A

Sedation dose: minimal effects

Induction dose: decreased BP and SVR

180
Q

Respiratory effects of midazolam?

A

Sedation dose: minimal effects

Induction dose: respiratory depressant

181
Q

Even when using the sedation dose for midazolam, what can potential respiratory depression?

182
Q

What patients are more sensitive to the respiratory depressant effects of midazolam?

183
Q

CNS effects of midazolam?

A

Sedation dose: minimal effects on CMRO2 and CBF
Induction dose: decreases CMRO2 and CBF
Anterograde amnesia
Anticonvulsant
Anxiolysis
Spinally mediated skeletal muscle relaxation (antispasmodic)

185
Q

What is the elimination t 1/2 of diazepam?

186
Q

Why does diazepam remain in the body for such a long time?

A

It undergoes enterohepatic recirculation

187
Q

How long can lorazepam’s amnestic action persist?

A

Up to 6 hours

188
Q

Why is lorazepam not the best choice for anticonvulsant?

A

Slow onset

189
Q

Put midazolam, diazepam and lorazepam into relative potency greatest to least

A

Lorazepam > midazolam > diazepam

190
Q

What is added to diazepam and lorazepam to enhance water solubility that is not needed in midazolam?

A

Propylene glycol - this causes venous irritation (diazepam > lorazepam)

190
Q

What is done after the initial dose of flumazenil?

A

It is titrated in 0.1 mg increments every 1 minute

191
Q

What is Flumezenil?

A

A competitive antagonist of the GABA-A receptor

193
Q

What is the duration of flumazenil?

A

30 - 60 minutes

194
Q

What is the initial dose of flumazenil?

195
Q

What effect does flumazenil have on reversing the sedative and amnestic effects of benzodiazepines?

A

It tends to reverse the sedative effects more than the amnestic effects

196
Q

What is the plasma protein binding of:
Midazolam
Diazepam
Lorazepam

A

Midazolam: 94%
Diazepam: 98%
Lorazepam: 90%

Apex (46 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions