NMB: Part 2 - Reversal Flashcards
What are the clinical uses of anticholinesterase drugs?
REversal of NMBD
Antagonism of CNS effects on other drugs
Treatmetn of MG or glaucoma
What is the mechanism of action of anticholinesterase drugs?
NMJ effects due to inhibition of acetylcholinesterase
What are the three classifications of anticholiesterase drugs?
Reversible inhibition
formation of carbamyl esters
Irriversible inactivation
How is edrophonium classified?
reversible inhibition
What is echothiophate and how is it classified?
It is an organophosphate used in pesticide. It is classified as irreversible inactivation
Neostigmine, Physostigmine and pyridostigmine. How are they classified and which one is different?
Formation of carbonyl esters.
Physostigmine is the only one that crosses the blood brain barrier.
(the only one with an H goes to the Head)
How do Pyridostigmine, Neostigmine and edrophonium compare in onset and duration of action?
Edrophonium is short, neo in the middle and Pyridostigmine is longest onset/duration.
How are anticholinesterase drugs eliminated?
50-75% of elimination is via renal clearance
Could you give anticholinesterase to a pt with renal failure?
Yes, it would have prolonged effect, but so would your relaxant, so its cool
How does age affect neostigmine?
children and infants require less
What effects do anticholinesterase drugs have on the cardiovascular system?
Bradycardia
What effects do anticholinesterase drugs have on the GI/GU systems?
Increased secrtion and motility
Tx of paralytic ileus or atonic bladder
What effects do anticholinesterase drugs have on the secretory glands/airways?
Increased secretions and bronchoconstrictions
Increased secrtions in bronchial, lacrimal, sweat, salivary, gastric and intestinal
Which neurologic disorder do anticholinesterase drugs treat?
MG
What is the treatment for Anticholinesterase OD?
Atropine with pralodoxime (cholinesterase reactivator)
What are the nicotinic and CNS symptoms of anticholinesterase OD?
Nicotinic -from skeletal muscle weakness to paralysis resulting in apnea CNS -confusion -ataxia -siezure -coma -depression of ventilation
What is the dose for Neostigmine?
0.04-0.07 mg/kg
Is 5 mg the max dose for neostigmine?
NO!!! Above 5mg increases the chance PONV, but it is not a max
What is the rule for when a pt may be reversed?
The absence of any palpable single twitches following 5 s of tetanic stimulation at 50Hz implies very intensive blockade that cannot be reversed
What is onset, peak and duration of neostigmine?
ONset-5-10 minutes
Peak-10 minutes
duration-1 hour
How do anticholinergics work?
they prevent Ach binding at muscarinic receptors
reversible bond to Ach receptor
can be overcome with increased Ach
What are the effoects of anticholinergics?
Sedation (atropine and scopalamine) Antisialagogue Increase HR Relax smooth muscle Mydiasis Prevent motion sickness Decrease gastric ion secretion
Why do we use glyco instead of atropine when giving neostigmine?
closest onset and duration compared to neo
How are anticholinergics cleared?
Cleared unchanged in urine. but its not really a big deal for renal pts
How do you administer atropine, and glyco?
IM or IV. Po is unpredictable
What is the lipid solubility of atropine, glyco and scopalamine?
scopalamine and atropine are lipid soluble
glyco is not
What are clinical uses for anticholinergics?
Important -Pre op med -tx of bradycardia -NDNMB reversal Less common -Bronchodilation -Smooth muscle relaxant (biliary and uretal) -Antagonism of gastric acid secretion (Not used since the dose needed is very high and better drugs are available) -Prevents nausea and vomiting
HOw would anticholinergics affect glaucoma?
make it worse
Do anticholinergics cross the placenta?
Yes, but it’s not a big deal for the baby
Which anticholinergic is the most potent sedative? Where does it work?
scopalamine
works at reticular activating system
4 mg IV is a good dose. Will cause amnesia
Why would atropine be a bad choice for sedation?
causes memory deficit and delayed arousal
How much glycopyrolate do you give for sedation?
glyco has no sedation effects
Which anticholinergic is the most potent antisialogogue?
Scopalamine
3x more potent than atropine with less HR changes
how does glyco compare to atropine as an antisialogogue?
2x more potent
Useful when sedative effects are not wanted
How do anticholinergic drugs work to treat bradycardia?
Blocks Ach @ SA node
How does glyco compare to atropine for treating bradycardia?
equal in effectiveness, but the onset of glyco is slower
What is the mechanism for anticholinergics causing bronchodilation?
block the muscarinic receptors of the smooth muscle of medium and large AW leading to decreased resistance and increased deadspace
What is the anticholinergic drug used for bronchodilatin? what is it called when its combined with albuterol?
ipratropium bromide (atrovent) combivent
Can anticholinergic drugs be used to treat narcotic induced biliary constriction?
no
What are symptoms of central anticholinergic syndrome?
restlessness
hallucinations
somnolence
unconsciousness
What is the treatment for central anticholinergic syndrome?
Physostigmine-it crosses BBB
Which pts are susceptible to central anticholinergic syndrome?
Children and elderly
What dose of glyco causes central anticholinergic syndrome?
It does not cross into the central nervous system, so it wont cause CAS. It is most common with scopalamine, but can be caused by atropine
What are the symptoms of anticholinergic OD?
Dry mouth blurred vision tachycardia Increased temp flushing irritability
What are the effects of anticholinergic OD?
Seizures
coma
ventilatory paralysis
What is the treatment for anticholinergic OD?
physostigmine
What are criteria for a pt being reversed?
TOF ratio >0.7 tetanus with 100 Hz stimulation Grip strength Negative inspiratory pressure > 20 cm H2O Sustained head lift = 5 seconds
What nerves do we use to monitor TOF?
Ulnar nerve
Posterior Tibial
Peroneal
Facial nerve
What’s so special about Sugammedex?
Works independent of Ach level in NMJ-so a profound block with no twitches can be reversed
Cleared renally but speed of reversal is independent of renal function
No need for muscarinic antagonist
Still awaiting approval-some evidence of anaphylactic reaction
