Neuromuscular blocking agent reversal (13) Flashcards
to reverse the effects of those badass blockers when we fuck up and gave too much (opps). Just make sure you have at least 1 twitch (it helps)
What do you call a CRNA who graduates school in last place and has the lowest passing scores on the boards????
A CRNA (bitch)!!!!!!!!!!
2 parts of the CNS
- brain
- spinal cord
2 parts of the PNS
somatic nervous system (SNS)
Autonomic nervous system (ANS)
Which system conveys information from receptors to the CNS
Afferent system
which system conveys information from the CNS to the muscles and glands
Efferent system
what are the 2 main areas the efferent system sends information to?
the somatic nervous system (SNS)
and Autonomic nervous system (ANS)
what does the somatic nervous system (SNS) do
conveys informatin from the CNS to the skeletal muscles
what does the ANS do
conveys information from the CNS to smooth muscle
cardiac muscle
and glands
diagram of CNS and PNS
C Brain Spinal Cord
N ^ v
S Afferent Efferent
V V
P Somatic Autonomic
N Nervous Nervous
S System System
V V
SNS PNS
2 parts of the ANS
Sypathetic nervous sytem
parasympathetic nervous system
ACh is stored where at the synaptic cleft
in vessicles at motor end plate
the nicotinic ACh receptor consist of how many gycoproteiin subunits to form an ion channel? what are the named?
5
- 2 alpha
- 1 beta
- 1 delta
- 2 gamma (epsilon)
how many alpha glycoprotein subunits on the nicotinic receptor need to bound to for ACh to open the channel
(both) 2
how many alpha glycoprotein subunits on the nicotinic receptor need to bound to for NDMBs to block the channel
1
how many alpha glycoprotein subunits on the nicotinic receptor need to bound by Sux’s to cause a block
both (2)
how is reversal of NMB (neuro muscular blockade) achieved
by competitive antagonism
- -competition b/t NMBA and ACh for the motoer end plate receptor at the NMJ
- whichever is the greatest wins
what is RECURARIZATION?
was a problem with long acting NMBAs whose effects outlasted the reversal agents
what is ENCAPSULATION reversal
cyclodextrin surrounds and bonds NMBA in plasma
-the concenration gradient reversed drawing NMBAs off receptors into plasma and then quickly bound
side notes about cholinesterase inhibitors
what were they derived from?
what were they used for?
precursor of what (give ex)
derived from Calabar bean used in West africa as a poison precursor for organphosphates -insecticides -nerve gas
what class of drugs are reversal agents
cholinesterase inhibitors
basic way cholinesterase inhibitors work for reversals
competitive antagonism
- inhibits acethlcholinesterase (and other chilinesterases)
- so it increases the concentration of ACh at NMJ
Name 4 cholinesterase inhibitors
Edrophonium (Enlon)
Neostigmine (prostigmin)
pyridostigmine
Physostigmine (antilerium)
what is the most rapid acting cholinesterase inhibitor
edrophonium
which cholinesterase inhibitor binds REVERSIBLY to the negative charged enzyme site (cholinesterase enzyme)
edrophonium
wy is the duration of binding short with edrophonium
b/c once it binds it is liberated finds another site to bind to, and so on
why is edrophonium not recommended for deep blocks
b/c of the type of bonds it makes (reversable it’s not a covalent bond)
does edrophonium require attenuation of muscarinic response to ACh accumulation?
yes
just b/c shores may ask what is the basic chemical make up of edrophonium
simple alcohol with quaternary ammonium group
just b/c shores may ask (b/c he is jealous that jake is a fucking wizard) what is the basic chemical make up of Neostigmine
Quaternary ammonium compound
does Neostigmine cross the BBB
No way
what kind of bond does Neostigmine make
IRREVERSABLE enzymatic deactivation (covalent)
lipid solubility of Neostigmine
poor
onset and duration of Neostigmine
onset 4-8 minutes
duration 1 hour (can last up to 4)
does Neostigmine require attenuation of muscarinic response to ACh accumulation
you bet your ass it does
which Cholinesterase inhibitor is used for myasthenia gravis??? Hmmmmm
pyridostigmine
is pyridostigmine a long acting or short acting cholinesterase inhibitor
long
is pyridostigmine used in anesthesia
no (remember myasthenia gravis)
what is a cholinesterase that is a precusor of neostigmine and is a teriary amine
physostigmine (antilerium)
seems important b/c it is totally different
what is special about physostigmine (antilerium)
it crosses the BBB increasing the ACh in the brain causing: confusion lethargy weakness ***CHOLINERGIC CRISIS****
what is physostigmine (antilerium) used for??
counteract delerium caused by benzos and barbs
hint: physostigmine (antiLERIUM)=deLERIUM
all cholinesterase inhibitors are eliminated where
renal
endophonium 70%
Neostigmine 50%
Side effects of cholinesterase inhibitors
Bradycardia
bronckospasm
increased airway secretions
nausea
vomiting
abd cramping
miosis (constriction of pupil)
vision disturbance
micturation (voiding, peeing, weeing, pissing, etc)
so basically you go into a cholinergic chrisis
SLUDGE (too much ACh at postsynaptic cleft thus extreme PNS activation)
**so with doses he said he only expects us to know neostigmine I am going to include endophonium also for KNOWLEDGE b/c that is in out top drawer as well. all others are not in our immediate use
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*******Neostigmine******** dose (mg/kg) MAX DOSE onset (min) duration Renal exretion gycopyrrolate(mcg/kg) atropine (usually not needed)
dose--0.035-0.07 mg/kg MAX DOSE-- 5mg onset (min)- 7 min duration-- 55-75min (1hr-1hr 15 min) Renal exretion- 50% gycopyrrolate-- 7 mcg/kg atropine- 15-30 mcg/kg (hint: know the max dose almost every pt will always get the max dose the only exception is the old lady with a hip fracture for example a 70 kg pt X 0.07= 4.9mg so anyone who is over 70 kg will just get the MAX amount.
just look at this and see the differences no need to memorize endrophonium dose (mg/kg) MAX DOSE onset (min) duration Renal exretion gycopyrrolate(mcg/kg) atropine
dose 0.5-1 mg/kg MAX DOSE 40 mg onset (min) 1 min duration 40-65min Renal exretion 70% gycopyrrolate ( do not use ) atropine (7-10mcg/kg) ok so what to get out of it --compared to neostigmine endrophonium is: dose is twice as much more rapid onset shorter duration and don't use glyco
So here is a question!!! if you had to get your pt reversed as quick as possible what would you give???
(he specifically asked this in his lecture)
endrophonium
whats another name for cholinesterase inhibitor “antidotes”
anticholinergic agents
or parasympatholytics
what are 3 main anticholinergic agents, and there basic chemical coumpoud
atropine-tertiary Amine
scopolamine- tertiary Amine
gylcopyrolate- quaternary amine
should you give cholinesterase inhibitors without an anticholinergic
no
why is scopalamine rarely used
b/c of its significant central effects
****what are the general dosage recommendations for anti-cholinergics
gylcopyrrolate
glycopyrrolate- 7mcg/kg
–general rule of thumb neo and glyco are equal proportions 1cc to 1cc
what are the general dosage recommendations for anti-cholinergics
atropine
7-15 mcg/kg
given with endrophonium
how do you reverse children
you always give your anti-cholinergic, wait for an increased HR, then give the cholinesterase inhibitor
side effects of anti-cholinergic drugs
-tachycardia
-dry mouth
-mydriasis (dilated pupils)
-vision disturbance
-CONFUSION*
(opposite of cholinesterase inhibotors)
**what shores whats us to know about sugammadex ( he stated in his lecture just know this)
- cyclodextrin structure
- not used in the US
- causes encapsulation
