Neuromuscular Blockade NMB Flashcards
Describe the Nm nicotinic receptor
5 subunits
2 binding sites
2 gates - one upper and one lower
Lower gate is time dependent to close and reopen
Do drugs act on the ligand or the voltage gated channels?
Ligand gated
Need enough NT released from the ligand gated to stimulate a depolarization and get opening of the voltage gated receptor.
Describe a “non depolarizing” antagonist
Competitive and reversible!
Bind receptor and prevent ACh from binding.
Inhibit mm contraction
Can use AChE inhibitor to reverse effect and compete
Name a non-depolarizing blockade drug?
Tubocurarine
What are the names of the non depolarizing drugs?
Describe their effects
“-curium” and “-curonium”
NO CNS effects!
These pts are wide awake but totally paralyzed
Give IV
Name a non depolarizing drug with the fastest onset?
Rocuronium - 1-2min onset
INTUBATION
Describe the order of muscle paralysis with a non depolarizing drug.
Small mm first (hand, eye, larynx)
Diaphragm is last to go, but FIRST TO RECOVER.
Thumb is last.
Describe the prototype depolarizing NMB drug?
Succinylcholine
Depolarizes before blocks
Initial contraction before paralysis (sore mm next day)
Brief action, rapid onset.
What is the use of the dibucaine number?
To see if someone will have an abnormal reaction to the metabolism of succinocholine.
Describe a phase 1 blockade with succinylcholine?
prolonged depolarization –> spreads –> fasciculations
–> eventually get flaccid paralysis
NOT REVERSED WITH AChE inhibitors!
NON COMPETITIVE - can’t reverse!
Name a risk factor of the use of succinylcholine?
Hyperkalemia when nicotinic receptors stim.
Cardiac arrest
Name a few populations who should not be treated with succinylcholine?
Burn patients Denervated muscle (quadriplegia) Rhabdomylosis
receptors sensitize and upregulate –> so can see hyperkalemia
Describe the N(subN) receptor?
Found at ganglion.
How does a ganglion blocker work?
Blocks nicotinic receptors at all autonomic ganglia
Non depolarizing competitive antagonist
Decreases total output of ANS
Contrast the difference in molecule size between those that bind Nm and those that bind Nn receptors?
Nm –> neuromuscular –> 10C space for molecule
Nn –> ganglion –> 6C space for molecule
