Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Anesthesia Pharm (A) > Non-Depolarizing Muscle Relaxants (3) > Flashcards

Non-Depolarizing Muscle Relaxants (3) Flashcards

1
Q

How do we decide which NDMB to use?

A

influenced by differences in
* Onset
* Duration of action
* Rate of recovery
* Metabolism

usually base choice on DOA and comorbidities of the pt

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

What is the MOA of NDMB?

A
  • Act at pre-junctional sites to block Ach release
  • Competitive inhibitors for alpha subunits on nACHRs
  • Bind and do not cause conformation change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are characteristics of NDMB associated with nerve stimulation and reversals?

A
  • Decreased twitch response to a single stimulus
  • Unsustained response (fade) to continuous stimulus
  • TOF ratio < 0.7
  • Post-tetanic potentiation
  • Potentiation of other non-depolarizing drugs
  • Antagonism by anticholinesterase drugs
  • No fasciculations during onset
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the “fade” with NDMB suggest?

A

Some fibers are contracting while some are blocked

  • some are more susceptible to NMBD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are adverse side effects to NDMB?

A
  • Cardiovascular effects
  • Critical illness myopathy
  • Altered responses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What causes cardiovascular effects associated with NDMBs?

A
  • release of histamine
  • effects at cardiac muscarinic receptors
  • effects on nAchRs at autonomic ganglia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the cardiovascular effects associated with NDMBs?

A
  • Varies between patient d/t underlying disease and preop meds
  • rarely clinically significant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a autonomic margin of safety?

A

Difference between dose that produces blockade (ED95) and dose that creates circulatory effects

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

What is the autonomic margin of safety for pancuronium?

A

Same as the normal dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is critical illness myopathy?

A

Skeletal muscle weakness

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

When can critical illness myopathy occur?

A
  • Weeks to months after NMBD discontinued
  • patient with multiorgan fx vent >6 days
  • usually from aminosteroid blocker
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What potentially enhances risk of critical illness myopathy?

A

Large dose glucocorticoids prior to NMBD

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

What is the MOA of critical illness myopathy?

A

unknown

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

Why do you want to stick with the same NDMB once you pick one?

A

If you switch to another one to redose then they compound on each other and it will be hard to get pt reversed

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

How do volatiles affect NMBs?

A

Dose dependent enhancement of muscle relaxation with onset as early as 30 minutes

Des>Sevo>Iso

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

What are some drugs that enhance or antagonize blockade and what is the MOA?

A

Diuretics, Corticosteroids, Metoclopromide, LA

  • increase Ach release
  • depression of cholinesterase activity
  • depression of nerve conduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Magnesium ________ blockade of NMBs

A

enhances

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

What is MOA of magnesium increasing non depolarizing NMBs?

A
  • decreases prejunctional release of Ach
  • decreases sensitivity to postjunctional membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does giving ephedrine prior to non-depolarizing NMBs cause?

A

Decrease onset time from increase in CO and skeletal muscle flow

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

How does esmolol prior to induction affect non-depolarizing NMBs?

A

delays onset of the paralytic

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

Why is it important to prevent hypothermia in patients?

A

Even mild hypothermia double duration of vec and pancuronium through slowing of hepatic enzyme activity

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

Which NDMB are somewhat temperature dependent on metabolism?

A

Atracurium and Cisatracurium
- hoffman elimination and ester hydrolysis (need to have pretty close to normal body temp or the drugs action will be prolonged)

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

What changes in potassium are associated with NMBDs?

A

Acute hypokalemia
- hyperpolarize the cell
- resistance to depolarizing NMBDs
- increased sensitivity to non depolarizing NMBD
Acute hyperkalemia
- decreases Vrm (partial depolarizes cell)
- increases effects of depolarizing NMB
- resistance to non-depolarizing NMBs

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

When do burn patients have increased resistance to non-depolarizing NMBs?

A

10 -60 days post injury → need more of drug to have the same effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Double the dose of __________ will have onset similar to succinylcholine
Rocuronium (1.2mg/kg) double length of paralytic though
26
What are NMBD considerations for a patient that has paresis/hemiplegia?
- paralyzed arm: nAChRs are resistant to muscle relaxant compared to unaffected side - unaffected arm: still somewhat resistant to the muscle relaxant compared to normal patient
27
What is the MOA of resistant to NMBD on affect side of a stroke compared to unaffected side?
Proliferation of extrajunctional nAchRs
28
Which NMB is most likely to cause an allergic reaction?
Succs (although still uncommon) likely more of a histamine reaction
29
Which NMB is the least likely to cause an allergic reaction?
Cisatracurium
30
What can cause cross reactivity with NMB?
Quaternary ammonium group→ seen with soaps and cosmetics that can cause allergic reactions with NMBDs
31
Why are women more sensitive to NMBDs than males?
Women have less muscle mass and more fat (NMB lasts longer) - need 22% less Vec - need 30% less Roc
32
What is the TI for pancuronium?
1: toxic dose is the same a effective dose
33
What is the intubating dose, onset, and duration of Pancuronim?
0.1 mg/kg Onset: 3-5 min Duration: 60-90 min
34
What is the main reason pancuronium isnt used?
Vagolytic properties (tachycardia)
35
What is the metabolism of Pancuronium?
80% elimination unchanged in urine
36
How does elimination of pancuronium change in renal failure, liver disease, and aging?
In renal failure - 30-50% decreased plasma clearance - 10-40% deasacetylpancuronium metabolite ½ as active (by liver) In liver disease - Increased VD - Larger initial dose is needed Prolonged elimination ½ time In aging - Decreased plasma clearance d/t renal function
37
What are CV effects of Pavulon?
↑ HR, MAP, CO - d/t vagal blockade - Mostly at SA node - BP increase d/t HR d/t SNS activation - Release of NE presynaptically - Blockade of NE reuptake No changes in SVR or inotropy No histamine release
38
How do you decide which intermediate acting NMBD if they all have the same onset and duration?
Look at differences in metabolism (co-morbidities of the patient)
39
Onset, duration, CV effects of intermediate NMBs compared to Long acting NMBs:
- Similar onset of maximum blockade (except high dose roc) - Approximately 1/3 duration of action - Minimal/absent cardiovascular effects - Antagonized by anticholinesterase drugs approx 20 min.
40
What is the dose, onset, duration, and trade name for Vecuronium?
- Norcuron - 0.1mg/kg - O: 3-5 min - D: 20-35 minutes to be reversible
41
How is Vecuronium metabolized/excreted?
- Hepatic metabolism: Primary organ of elimination (70%) - Metabolite: 3-desacetylvecuronium 50-80% as potent but rapidly converted to metabolite 1/10 as potent - Renal excretion: 30% unchanged, prolonged 1/2 time with renal dysfxn
42
What are considerations when giving Vec to elderly pts?
- Decreased Vd (less muscle mass) - Decreased plasma clearance (less hepatic flow)
43
What are considerations with Vec and pregnant women?
- insignificant effects to fetus - increased clearance in 3rd trimester (progesterone) - prolonged duration early postpartum (give IBW)
44
How does acid-base imbalances affect blockade with Vecuronium?
Depends on when the acid-base status changed - Prior to NMBD→ no prolonged block - Resp Acidosis after NMBD given→ prolonged block
45
How does acidosis affect MOA of Vec?
- Acidosis decreases bound amount→ paralyzed longer than if pH was normal - change in ionization at receptor increases attachment time
46
What would be a concern in post op if patient had vec during procedure?
Hypoventilation→ acidosis
47
What are CV effects of Vec?
none and no histamine release 🤠
48
What is the dose, onset, duration, and trade name for Rocuronium?
- Zemuron - 0.6 mg/kg or 1.2 mg/kg (high dose parallels to succs onset but pancuronium offset) - O: 3-5 min, 1-2 min (high dose) - D: 20-35 min, 60-90 min (high dose)
49
How is Rocuronium metabolized?
- Excreted unchanged in bile (longer DOA in liver fx and elderly d/t decrease clearance and increase Vd) - 10-30% renal excretion (marginal affect in renal fx)
50
What NMBDs would we want to avoid in liver pts?
Vecuronium Rocuronium
51
What are CV effects of Rocuronium?
none, no histamine release
52
What is the dose, onset, duration, and trade name for Cisatracurium?
- Nimbex - 0.1mg/kg - O: 3-5 min - D: 20-35 min
53
How is Nimbex metabolized?
Degradation - Hoffman elimination (temp dependent) - Doesnt use non-specific plasma cholinesterases as much as Atracurium
54
Cisatracurium is the ____ isomer
Cis (no histamine) Recovery from infusion not affected by time
55
What pt pops affect pharamcokinetics of Nimbex?
- Elderly: delay in onset (1 min) d/t CO - Obese: DOA prolonged if dosed on actual body weight d/t Vd
56
What are CV effects of Nimbex?
None, no histamine release
57
Are there any short acting non-depolarizing NMBDs on the market currently?
Nope
58
What is the dose, onset, duration, and trade name of mivacurium?
- Mivacron - 0.15mg/kg - O: 2-3 minutes - D: 12-20 minutes (short)
59
Why is Mivacron no longer on the market?
Did not provide a great paralysis "MOVE-acron🥴"
60
What was Mivacron good for when it was in clinical use?
Super fast procedures: - drilling pin in finger - mediastinoscopy for node biopsy in trachea
61
How it mivacurium metabolized?
3 stereoisomers - Cis-cis - Cis-trans (NM blocking ability) - Trans-trans (NM blocking ability) Cleared by plasma cholinesterases
62
What CV effects are associated with Mivacron?
Minimal Histamine release - >3X ED95 (transient MAP drop) - more common with rapid, large doses - MAP drop more in HTN pts

Anesthesia Pharm (A) (19 decks)

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