Medical Pharmacology: Neuromuscular Junction Blocker Practice Questions
NMJ blockers characteristic(s):
- highly lipid-soluble
- structural similarity to acetylcholine
- both
- neither
Isoquinoline derivative:
- pancuronium (Pavulon)
- vecuronium (Norcuron)
- doxacurium (Nuromax)
- pipecuronium (Arduan)
- roncuronium (Zemuron)
Nondepolarizing neuromuscular agents -- elimination characteristics
- agents with renal elimination: shorter half lives
- agents with hepatic elimination longer half lives
- both
- neither
Hofmann elimination:
- tubocurarine
- mivacurium (Mivacron)
- atracurium (Tracrium)
- cisatracurium (Nimbex)
- doxacurium (Nuromax)
Mainly hepatic (75-90%) elimination; usually shortest duration of action
- pancuronium (Pavulon)
- pipecuronium (Arduan)
- roncuronium (Zemuron)
- all of the above
Isoquinoline derivative; shortest duration of action
- cisatracurium (Nimbex)
- tubocurarine
- mivacurium (Mivacron)
- vecuronium (Norcuron)
Shortest duration of action: neuromuscular-blocking --
- mivacurium (Mivacron)
- gallamine (Flaxedil)
- pipecuronium (Arduan)
- succinylcholine (Anectine)
- all of the above equally short
Most commonly used class of neuromuscular-blocking drugs:
- intermediate-acting
- long-acting
For elimination, vecuronium (Norcuron) & roncuronium (Zemuron) depend mainly upon this mechanism:
- renal excretion
- hepatic metabolism & biliary excretion
Most rapid onset among nondepolarizing blockers --
- vecuronium (Norcuron)
- pancuronium (Pavulon)
- pipecuronium (Arduan)
- roncuronium (Zemuron)
Shortest duration of action among nondepolarizing neuromuscular blocking drugs:
- pancuronium (Pavulon)
- pipecuronium (Arduan)
- tubocurarine
- mivacurium (Mivacron)
Mechanism of termination of action of succinylcholine (Anectine):
- reuptake into presynaptic vesicles
- diffusion away from postsynaptic receptors
- metabolism by postsynaptic acetylcholinesterase
Succinylcholine (Anectine): duration of action
- 5-10 minutes
- 15-30 minutes
- > 30 minutes
Dibucaine (Nupercainal, generic) number. indicative of possible abnormality in:
- tyrosine hydroxylase
- monoamine oxidase
- catechol-O-methyltransferase
- plasma cholinesterase
- none of the above
Neuromuscular-blocking drug pharmacodynamic characteristics are determined by measuring:
- speed the onset
- duration of neuromuscular-blockade
- both
- either
Effect of volatile anesthetics on ED95 for neuromuscular-blocking agents:
- usually increases ED95
- usually decreases ED95
Sequence of events following IV neuromuscular-blocking injection (nondepolarizing drug) to an awake patient:{first presentations to last}
- dysphagia, diplopia, ptosis,difficulty in focusing, mandibular muscle weakness
- mandibular muscle weakness, ptosis, dysphagia, difficulty in focusing
- difficulty in focusing, mandibular muscle weakness, ptosis, diplopia, dysphagia
- all symptoms occur simultaneously
Blockade onset (nondepolarizing agents): more rapid, less intense at laryngeal muscles (vocal cords) first, then adductor pollicis
- true
- false
Intensity of initial blockade: greater at laryngeal muscle, less at adductor pollicis
- true
- false
Neuromuscular diaphragm blockade:
- requires 2x the dose required for adductor policies muscle blockade
- adductor pollicis monitoring; poor indicator of cricothyroid muscle (laryngea) relaxation
- facial nerve stimulation with orbicularis oculi muscle responds monitoring -- good reflection of neuromuscular diaphragm blockade onset
- orbicularis oculi muscle monitoring: preferable to monitoring adductor pollicis as indicator of laryngeal muscle blockade
- all of the above
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