Reversals Flashcards
What is the MoA of antichoinesterases?
increase concentration of ACh at nicotinic receptors by enzyme inhibition (inhibit AChE preventing hydrolysis of ACh which increases conc of ACh at nicotinic and muscarinic receptors) and presynaptic effects (stimulates presynaptic nicotinic receptors to increase release of ACh.
True/False. Anticholinesterases inhibit BOTH true cholinesterase and pseudocholinesterase.
True
True/False. Anticholinesterases can cause prolonged effect of Succ and other drugs.
True, inhibits pseudocholinesterase which breaks down succ, ester locals, and remi which can cause prolonged effects.
What is the primary goal of reversal?
to maximize NICOTINIC TRANSMISSION, while minimizing MUSCARINIC SIDE EFFECTS
What are the cholinergic side effects?
DUMBBELLS Diarrhea, Urination, Miosis, Bradycardia, Bronchoconstriction, Emesis, Lacrimation, Laxation, Salivation.
By increasing the concentration of ACh at the muscarinic receptors, AChE inhibitors cause a predictable set of __________ ____ ________.
parasympathetic side effects
What 3 ways can anticholinesterases inhibit AChE?
electrostatic attachment, formation of carbamyl esters, and phosphorylation
What are some drug examples of inhibiting AChE by electrostatic attachment?
edrophonium, reversible/weak bonds, short DoA
What are some drug examples of inhibiting AChE by formation of carbamyl esters?
neostigmine, pyrido, physo, intermediate DoA
What are some drug examples of inhibiting AChE by phosphorylation?
organophosphates and echothiophate, irreversible/inactivation, long DoA
What determines the duration of action of all of the cholinesterase inhibiting drugs
the strength of the bond that is formed during hydrolysis
Discuss the pharmacokinetics of cholinesterase inhibiting drugs.
large Vd, 50-75% renal/25-50% hepatic, conjugated, hydrolyzed, and metabolized in LIVER, poorly lipid soluble, quaternary amines and DON’T pass BBB.
What is the exception to passing the BBB for anicholinesterases?
physostigmine (tertiary amine and does pass BBB)
Is edrophonium recommended for profound NMB?
No, short DoA.
What are the uses of edrophonium?
antagonize NDMR, diagnoses/assess therapy for myasthenia gravis and cholinergic crisis, evaluate presence of dual blockade of succ (assess phase 1 or 2)
What are the uses of neostigmine?
antagonize NDMR (most commonly used), treatment of myasthenia gravis
What are some uses of physostigmine
treatment of choice for anticholinergic syndrome d/t atropine poisoning, reverse prolonged somnolence (diazepam, scopalamine, inhaled agents), antagonize opioid induced resp depression, treats postop shivering,
What is special about physostigmine?
it is almost completely metabolized by plasma esterases; only anticholinesterase to cross the BBB (tertiary amine and lipid soluble)
What is echothiopate used for and its considerations?
treat glaucoma, irreversible bond formed to AChE, may prolong Succ block because also inhibits pseudocholinesterase.
Describe anticholinesterase poisoning.
organophosphate compounds are used as insecticides and applied as aerosols which can be rapidly absorbed through the skin and mucous membranes. Occurs at cholinergic junctions such as postganglionic parasympathetic junctions, autonomic ganglia and NMJ.
What are the muscarinic signs of anticholinesterase poisoning?
SLUDGE: Salivation, Lacrimation, Urination, Diaphoresis, Gastrointestinal upset, Emesis. progresses to bronchospasm, blurred vision, brady/tachy, hypotension, confusion, shock.
What are the nicotinic effects of anticholinesterase poisoning?
skeletal muscle initially exhibits fasciculation followed by inability to repolarize cell membranes causing weakness and paralysis
What is the treatment for anticholinesterase poisoning?
atropine 1-2mg IV q3-5 min, pralidoxime 15mg/kg IV over 2 min
What is central cholinergic syndrome?
Cholinergic crisis, OD of cholinesterase inhibitors, excessive ACh in brain; S&S: N/V, brady/tachy, salivation, sweating, bronchospasm, weakness/paralysis.
What is the treatment for central cholinergic syndrome?
atropine 10mcg/kg q3-10 min w/vent support until muscarinic sx decrease
What are other words for anticholinergics?
antimuscarinics, parasypatholytics
What is the MoA of anticholinergic drugs?
reversibly bind with muscarinic cholinergic receptors; preventing acetylcholine binding to these sites causing excessive PNS effects.
Do anticholinergics cause reversible/nonreversible blockade of ACh at muscarinic receptors?
reversible, competitive blockade. increased ACh can overcome anticholinergics.
What’s the biggest effect of atropine?
increase HR, also smooth muscle relaxation/bronchodilation
What are the biggest effects of scopolamine?
increased sedation, decreased oral secretions, mydriasis cycloplegia(dilation of pupil, loss of accommodation/blurred vision), prevent motion sickness
What is the biggest effects of glycopyrrolate?
increase HR, smooth muscle relaxation/bronchodilation, decreased secretions
What do anticholinergics do to the CNS?
mild stimulatory followed by slower, longer sedative effect
What do anticholinergics do to the eye?
dilation of pupil, paralysis of ciliary muscle causing loss of accommodation or blurred vision
What effects do anticholinergics have on CV system?
counteracts bradycardia, increased rate of SA node and AV conductance
What effects do anticholinergics have on resp system?
bronchodilation, decreased secretions
What effects do anticholinergics have on the GI tract?
decreased tone and motility
What effects do anticholinergics have on the bladder?
decreased tone, urinary retention
What are the clinical uses of anticholinergics?
concommitent use with anticholinesterases, parkinsons, motion sickness, opthalmologic disorderes, CV disorders/brady, cholinergic poisoning
What is atropine poisoning?
central anticholinergic syndrome: dry mouth, mydriasis, tachy, hot/flushed, agitation, delirium
How do you treat atropine poisoning?
physostigmine 15-60mcg/kg
What are contraindications to anticholinergics?
glaucoma and gastric ulcers
How do you administer anticholinesterases and anticholinergics together?
draw up separately, alternate 1cc at a time, don’t give all anticholinesterase before giving anticholinergic–profound brady.
How does sugammadex work?
ring encapsulates neuromuscular blocker and renders it ineffective/unable to engage with nicotinic receptor. doesn’t interact with receptors or neurotransmitters so NO systemic side effects.
What drugs does sugammadex not affect?
benzylisoquinoliums or succ.
What drugs does sugammadex work on?
roc, vec, pancuronium
What is the MOA of sugammadex?
selectively binds to aminosteroid NDMR
What are some advantages to sugammadex?
no effect on anticholinesterase, no effect on receptors/no side effects, mechanism of reversal independent of depth of block.
How quickly does sugammadex reverse patients?
reverses blockade to a TOF ration of >0.9 within 3 min
What are some side effects of sugammadex?
Hormonal contraceptives ineffective for 7 days, not recommended in severe renal imiparment; rare: brady, anaphylaxis, bleeding
What dose of sugammadex do you give for a moderate block/2 twitches?
2mg/kg
What dose of sugammadex do you give for a deep block/0 twitches?
4mg/kg
What dose do you give of sugammadex if you need to reverse within 3 min of giving Roc?
16mg/kg
True/false, you can give paralytic right after reversal with sugammadex?
false, use nonsteroidal NMB such as atracurium or cisatracurium (benzylisoquinoliniums). wait 24h for roc or vec if 16mg/kg given.
How much Roc do you give if you gave sugammadex 5min-4h ago?
1.2mg/kg
How much Roc and vec do you give if you gave sugammadex >4h ago?
0.6mg/kg; vec 0.1mg/kg