Nondepolarizing NMBDs Flashcards
What is the action of Nondepolarizing NMBDs?
act as competitive antagonists by binding to the α subunits of the nAChR
What do the Nondepolarizing NMBDs bind to?
to one of the α subunits
What does Nondepolarizing NMBDs binding cause?
doesn’t open channel, blocks depolarization
What are the classifications of Nondepolarizing NMBDs?
Chemical class & Duration of action
What are the different chemical class of Nondepolarizing NMBDs?
steroidal, benzylisoquinolinium
In general, dose of ________ ED95 is used to facilitate tracheal intubation and dose of ______ of the ED95 is used to maintain neuromuscular blockade
2-3x; 10%
What substance was the basis for development of the benzylisoquinolinium-type muscle relaxants? What historical impact did it have?
Curare (South American Indians’ arrow poisons)
What is tubocurarine? What was its only clinical use?
not currently in use anymore d/t side effects,
De-fasciculating dose (priming dose) 3 mg- primary purpose when it was used
What Benzylisoquinolinium Compounds are currently in use? (3)
Atracurium, Cisatracurium, Mivacuronium
What is the structure of Atracurium (Tracrium)?
Racemic mixture of 10 stereoisomers
What is the metabolism of Atracurium (Tracrium)?
Undergoes spontaneous degradation at physiologic temperature and pH by Hoffman elimination and can also undergo ester hydrolysis
What does metabolism of Atracurium (Tracrium) yield (2)?
yielding laudanosine and a monoquaternary acrylate as metabolites
What is laudanosine? What is its clearance?
is liver dependent for clearance, with 70% excreted in bile (excretion of this metabolite is impaired in patients with biliary obstruction)
What is the permeability of Atracurium (Tracrium) to the BBB and CNS?
Crosses blood brain barrier and has CNS stimulating properties
What can Atracurium (Tracrium) cause the release of?
histamine release
What is a potential quality of Atracurium (Tracrium) ?
Neuroprotective qualities?
What is the intubating dose of Atracurium (Tracrium)?
0.5 mg/kg
What is the onset of Atracurium (Tracrium)?
2-4 minutes
What is the duration of action of Atracurium (Tracrium)?
30-60 min. (intermediate acting)
What is the subsequent dose of Atracurium (Tracrium)?
0.1-0.2 mg/kg
What is the chemical structure of Cisatracurium (Nimbex)?
Cis isomer of atracurium
What is the potency of Cisatracurium (Nimbex)?
4-5 times more potent than atracurium
What is the metabolism of Cisatracurium (Nimbex)?
Metabolized by Hoffman elimination to laudanosine and a monoquaternary alcohol metabolite
How much of hoffman elimination accounts for the clearance of Cisatracurium (Nimbex)?
Hoffman elimination accounts for 77% of the total clearance and 23% is drug is cleared through organ-dependent means (renal elimination = 16%)