NMB Flashcards
Atracurium
Atracurium
class:
non-depolarizing neuromuscular blocker, benzylisoquinoline.
Quartenary ammonium compound, hydrophilic, does not cross BBB.
It is a competitive antagonist at the NMJ for acetylcholine receptors.
MOA:
Atracurium binds to acetylcholine receptors pre-synpatically at the NMJ to and prevents the mobilization of acetylcholine to the synapse, also binds post-synpatically at the NMJ to block acetycholine sites at acetylcholine recpetors and prevent membrane depolarizatoin and muscle contraction.
uses:
improve intubating conditions
facilitate ventilation
provides immobilization for surgery
pk:
PB: high
vD: 0.15 L/kg
onset: 3-5 minutes
DOA: 45 minutes
E1/2: 20 minutes
excreted in the urine
Metabolized 1/3 hoffman elimination, 2/3 ester hydrolysis.
Hoffman elimination is decreased with hypothermia or acidosis and increased with hyperthermia and alkalosis.
It has an inactive metabolite: laudanosine, that is a neurotoxin that can accumulate with renal insufficiency.
Atracurium is also a histamine releaser.
dose:
intubating dose: 0.5 mg/kg IV
re-dose for a 70kg individual: 10 mg
SE:
Histamine releaser - hypotension, facial flushing, tachycardia, bronchospasm
Seizures - r/t accumulation of laudanosine
C/I:
- caution in renal failure r/t accumulation of laudanosine
- caution in seizure hx r/t laudansoine
- caution in COPD, asthma r/t bronchospasm
- C/I in consicous patients
- caution with myasthenia gravis
Cisatracurium
Cisatracurium
Class:
Non-depolarizing muscular blocker. Benzylisoquinoline. INTERMEDIATE ACTING NMB. Competitive antaognists for acetycholine receptor ar the NMJ. It’s a quartenary ammonium compound, hydrophilic, does not cross BBB.
MOA:
Binds to acetylcholine receptors presynpatically at the NMJ to inhibit the mobilization of acetycholine to the NMJ, binds to acetylcholine receptors post synaptically at the NMJ to block acetycholine, prevent membrane depolarization, and prevent muscle contraction.
Uses:
Improve intubating conditions
facilitate ventilation
provide immobolity for surgery
pk:
PB: High
vd: 0.15 L/KG
onset: 3-5 minutes
DOA: 45 minutes
E1/2t: 30 minutes
eliminated in urine and feces
Metabolized 80% by Hoffman elimination. Hoffman elimination is prolonged with hypothermia or acidosis and shortened with hyperthermia or alkalosis.
Has an active metabolite: laudanosine but only produces 1/5 as much compared to atracurium.
dose:
Intubating: 0.2 mg/kg
Re-dose for a 70 kg individual would be 1-2 mg
SE:
Seizures - related to accumulation of laudanosine
can lower seizure thresshold
can have a prolonged NMB with certain abx (aminoglycosides, clindamycin), local anesthetics, and lithium.
C/I:
Consicous individuals
caution in renal failure and hx of seizures r/t laudansoine
caution in myasthenia gravis
Mivacurium
Mivacurium
Class:
Non-depolarizing neuromuscular blockade, benzoisoquinoline, shorting acting NMB. Competitive antagonist at acetylcholine receptors. Quartenary ammonium ion, does not cross BBB, is hydrophilic.
MOA:
Binds to acetylcholine receptors presynaptically at NMJ to block the mobilization of acetylcholine quanta to NMJ, binds to acetylcholine receptor post synpatically to block the membrane depolarization and subsequent muscular contraction.
Uses:
Improves ventilating conditions.
Facilitates ventilation.
Provides immobility for surgery.
Pk:
PB: High
Vd: 0.2 L/kg
Onset: 1-3 minutes
DOA: 10-20 minutes
Excreted 7% unchanged in kidneys
metabolized by plasma esterases, has no active metabolites
Mivacurium is a histamine releaser.
Dose:
0.2 mg/kg intubating dose
re dose for 70 kg individual: 1 mg
SE:
Histamine releaser - hypotension, flushing, bronchospasm, tachycardia
NMB can be prolonged with aminoglycosides, clindamycin, local anesthetics.
C/I:
caution in copd/asthma r/t bronchospasm
caution in CAD r/t hypotension, tachycardia
Pancuronium
Pancuronium
class: non-depolarizing neuromuscular blocker. Aminosteroid, long-acting neuromuscular blocker. quatenary ammonium compound, does not cross BBB, hydrophilic. Competitive antagonist at acetylcholine receptor.
MOA: Binds to acetylcholine receptors presynaptically to impair mobilization of acetycholine quanta to NMJ. Post synaptically binds to acetycholine, prevents membrane depolarization and muscle contraction. sdsd
Uses:
improves intubating conditions
facilitates ventilation
provides immobility for surgery
Pk:
PB: minimal
Vd: 0.3 L/kg
Onset: 3-5 minutes
E1/2T: 2 hours
DOA: 60-90 minutes
Metabolized by liver to active metabolite: desacetylpancuronium.
Excreted 80% unchanged in urine
Dose:
intubating: 0.1 mg/kg
SE:
10-15% increase in HR, CO, MAP r/t SNS stimulation
Increase HR even on beta blockers
Vagolytic action at heart.
Increased salivation,
bronchospasm
hypoventilation
C/I:
Renal failure
prolonged action in liver, renal diseaes
caution in CAD, CHF, pheochromacytoma
resp acidosis enhances DOA, makes NMB more resistant to reversal by neostigmine.
Rocuronium
Rocuronium
Class:
non-depolarizing neuromuscular blocker, aminosteroid, short/intermediate acting NMB. Quartenary ammonium compound, does not cross BBB, competitive antagonist at acetylcholine receptor.
MOA:
Binds to acetylcholine receptor presynaptically of NMJ to prevent mobilization of acetycholine quanta to NMJ, binds to acetycholin receptor post synpatically at NMJ to prevent membrane depolarization and muscle contraction.
Uses:
improves intubating conditions.
facilitates ventilation.
provides immobilization for surgery
Pk:
PB: 30-50%
Vd: 0.3 L/kg
Onset: 1-3 minutes
DOA: <30 minutes with lower doses,
30-60 mintues with higher doses
E1/2: 2 hours
Metabolized by liver
Excreted 50% in bile, 30% in urine.
Doses:
Shorter acting doses: 0.3 mg/kg
Intubating doses: 0.6-0.9 mg/kg
RSI: 0.9-1.2 mg/kg
De-fasiculating dose: 0.1 mg/kg
SE:
minimal, minimal increases in HR, decreases in BP
increased salivation, hiccups, bronchospasm
C/I:
conscious patients, hypersensitivy
caution in myasthenia gravis
caution with COPD/asthma r/t bronchospasm
DECREASE DOSE IN hepatic impairment
caution in renal failure, biliary tract impairment
caution in drugs that induce CYP450 enzymes and increase metabolism
Succinylcholine
Succinylcholine
class
Depolarizing neuromuscular blocker, partial agonist at acetylcholine receptors, its a quartenary ammonium compound, does not cross BBB, hydrophilic. It is structurally similar to two acetylcholine molecules stuck together.
MOA
Binds to acetylcholine receptors and causes partial membrane depolarization and muscle contraction, then remains bound to receptor ro prevent further depolarization and contraction, producing paralysis.
Uses
Improves intubating conditions.
Laryngospasm
Pk
PB: LOW!!!!!!!
Vd: 0.2 L/kg
Onset; 30-90 seconds.
E1/2T: 4 minutes
DOA: 9-13 minutes
Metabolized by psuedocholinesterase in plasma,
Succinylcholine is a histamine releaser.
Dose
Intubating dose: 1mg/kg
RSI: 1.5 mg/kg
Laryngospasm: 20 mg
SE
- Histamine release: tachycardia, flushing, hypotension, bronchsopasm
- Transient increase in potassium 0.5 -1 meq
- Fasiculations and myalgia
- Increase IOP
- increased IGP
- Increase ICP
- Bradycardia more likely in children
- tachycardia more likely in adults
- with additional doses, bradycardia in adults also
- Masseter spasm
- malignant hyperthermia trigger
- rhabdomyolsis, myoglobinuria
C/I
Burns, myopathy
Any prolonger >48 hours of immobility, muscular disuse
Duchene’s muscular dystrophy
Blackbox warning in pediatrics r/t r/f undiagnosed musuclar dystrophies
C/I with familial hx of MH
caution in COPD/ asthma r/t bronchospasm
Atypical pseudocholinesterase - low dibucaine number
Vecuronium
Vecuronium
Class: non-depolarizing neuromusclar blocker, aminosteroid. Competitive antagnoist at acetylcholine receptor. intermediate acting neuromuscular blocker. Quartenary ammonium copmound, hydrophilic, does not cross BBB.
MOA:
presynaptically binds to acetylcholine receptor to prevent mobilzation of acetylcholine quanta to NMJ, post synaptically binds to acetylcholine receptor to prevent membrane depolarization and muscle contraction.
uses
improves intubating conditions
facilitates ventilation
provides immobility for surgery
Pk
- PB: 60-80% (highest)
- Vd: 0.3 L/kg
- onset: 3-5 mintues
- E1/2t: 70 minutes
- DOA: 30 minutes
- Metablolized in the liver by CYP450, excreted in bile and urine
Active metbaolite: desacetyl-vecuronium (50% potency)
dose:
intubating: 0.1 mg/kg
RSI: 0.3 mg/kg
de-fasicuating: 0.01 mg/kg
SE:
Sinus node exit block , cardiac arrest have been reported
bronchospasm
C/I:
Liver disesae - decrease dose
caution in biliary tract disease / renal disease
caution in copd/asthma r/t bronchospasm
cautoin with hx of CYP450 inducing drugs will increase metabolism
