NMB Agents

Question 1

Succinylcholine

MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism

Answer 1

•Mechanism of action: Ach rec agonist → antagonist
oPhase I: end plate cannot repolarize bc SUX continues to bind Ach receptors
oPhase II: acts as NDMR w/ prolonged depolarization
•Therapeutic Effect: Muscle paralysis by Nic rec binding (1-3mins)
•Adverse Effects: Interactions
oPlasma Cholinesterase Inhib: prolong phase I block/intensify depolarization/reduce metabolism of sux
oPhase II enhanced by NDMR
oMH to those susceptible
oBradycardia
•DOA: Short (5-10)
•Onset: 0.5-1 min
•Initial dose: 3xED95 (1-2mg/kg)
•Toxic Dosing/Contraindications:
oNeuromuscular disease
oMH
oAllergy
oHomozygous to atypical plasma cholinesterase
o[K] > 5.5 mEq/L
oDenervation/Burns (up-regulation of nicotinic receptors)
•Metabolism: Plasma cholinesterase (pseudocholinesterase)

Question 2

Gantacurium (MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism)

Answer 2

oMechanism of action: nicotinic direct antagonist
oTherapeutic Effect: muscle paralysis
oAdverse Effects: 
oHistamine release
oBronchospasm
ohypotension
oOnset: 1-2 mins
oDOA: 4-10 mins (short)
oInitial Dose: ED95 (0.2 mg/kg) ED95 = 0.19 
Metabolism: Ester Hydrolysis

Question 3

Rocuronium (MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism)

Answer 3

oMechanism of action: nicotinic direct antagonist
oTherapeutic Effect: Muscle paralysis
oAdverse Effects: Histamine release/Bronchospasm/hypotension
oOnset: 1.5 mins
oDOA: 35-75 mins (Intermediate)
oInitial Dose: 3xED95 (0.8mg/kg) ED95 = 0.3
oToxic Dose:
oMetabolism: none/Eliminated by the liver and kidney

Question 4

Atacurium (MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism)

Answer 4

oMechanism of action: nicotinic direct comp antagonist
oTherapeutic Effect: muscle paralysis
oAdverse Effect:
oHistamine release
oHypotension and tachycardia
oSome decreased SVR
oCNS excitation/seizures (Laudanosine Metabolite) → due to Hoffman elmination
oRare anaphylactic reactions 
oOnset: 2.5-3 mins
oDOA: 30-45 mins (Intermediate)
oInitial Dose: 3xED95 (0.5mg/kg) ED95 = 0.2
oToxic Dose/Contraindications/Drug Interaction
oPotentiation w/ volatile agents 
oHypothermia
oRespiratory acidosis
oHypokalemia
oHypocalcemia
oHypermagnesia
oMetabolism: Hoffman elimination

Question 5

cis-atacurium (MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism)

Answer 5

oMechanism of action: nicotinic direct comp antagonist
oTherapeutic Effect: muscle paralysis
oAdverse Effect: Laudanosine metabolite → crosses BBB could induce seizures
oOnset: 2-3 mins
oDOA: 40-75 mins (Intermediate)
oInitial Dose: 3xED95 (0.2mg/kg) ED95 = 0.05
oToxic Dose:
oMetabolism: Hoffman Elimination

Question 6

Vecuronium (MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism)

Answer 6

oMechanism of action: nicotinic direct comp antagonist
oTherapeutic Effect: muscle paralysis
oAdverse Effect: lacks side effects of pancuronium
oPossible precipitation w/ Thiopental
oProlonged liver failure
oOnset: 2-3 mins
oDOA: 45-90 mins (Intermediate)
oInitial Dose: 3xED95 (0.12mg/kg) ED95 = 0.05
oToxic Dose:
oMetabolism: Hepatic

Question 7

Pancuronium (MOA/AE/Onset/DOA/Interactions and Contraindications/Metabolism)

Answer 7

oMechanism of action: nicotinic direct comp antagonist
oTherapeutic Effect: muscle paralysis
oAdverse Effect: 
oHypertension
oTachycardia (vagolytic)
oVagal blockade
oSympathetic stimulation
oOnset: 2-3 mins (Intermediate)
oDOA: 60-120 mins (Long)
oInitial Dose: 3xED95 (0.12mg/kg) ED95 = 0.07
oToxic Dose:
oMetabolism: Liver and excreted by the kidneys