Anticholinesterases and Anticholinergics
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Acetylcholine binds to ____________ and _____________ receptors | nicotinic
muscarinic
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The goal of reversing a NMB is to maximize _____________ receptor transmission by ACh and minimize ______________ receptor transmission | nicotinic
muscarinic
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How does anticholinesterase inactivate acetylcholine? | by binding to it
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Neostigmine, Pyridostigmine and Physostigmine are ________ by AChE & cause it to become carbamylated so they can _________ inhibit AChE's ability to hydrolyze ACh | hydrolyzed
reversibly
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Which reversal drug is thought to have presynaptic effects which cause an increase in the availability of acetylcholine? | edrophonium
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How it is possible for a reversal drug to actually enhance a neuromuscular blockade? | When the NMJ is flooded with ACh, it can becomes desensitized to ACh preventing ACh from competing with the NMB on the receptor and actually allowing the blockade to continue
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Edrophonium forms _________ bonds with AChE. These bonds are ________ lived, requiring a _________ dose and producing a _________ onset. | hydrostatic
short
higher
quick
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Neostigmine & Pyridostigmine form _________ bonds with AChE. These bonds last __________ than the bonds formed between Edrophonium and AChE | covalent
longer
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What is the dose of Edrophonium? | 0.5 - 1 mg/kg
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What is the onset and duration of Edrophonium? | onset: 30 - 60 seconds
duration: 30 - 60 minutes
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What is the dose of Neostigmine? | 0.06 mg/kg
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What is the maximum dose of Neostigmine? | 0.07 mg/kg
5 mg is MAXIMUM dose despite weight
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What is the onset and duration of Neostigmine? | onset: 7 - 11 minutes
duration: 45 - 90 minutes
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What is the dose of Pyridostigmine? | 0.3 mg/kg
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What is the onset of Pyridostigmine? | 10 - 20 minutes
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What is the dose of Physostigmine (Antilirium)? | 0.5 - 2 mg (0.01 - 0.03 mg/kg)
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Why do you have to give Physostigmine (Antilirium) slowly? | because it will cause projective vomiting if given quickly
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What is the onset of Physostigmine (Antilirium)? | 5 minutes
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Why is Physostigmine (Antilirium) typically given? | to treat Central Anticholinergic Syndrome (post op delirium)
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What is the mechanism of action of organophosphate anticholinesterase agents? | they form irreversible bonds with AChE, causing massive amounts of ACh to bind with muscarinic and nicotinic receptors
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What are some examples of organophosphate anticholinesterase agents? | echothiophate eye gtts, insecticides, nerve gas
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What does stimulation of cardiac muscarinic receptors by ACh cause? | bradycardia, junctional rhythms, PVCs, ventricular rhythms, asystole, and slowing of AV conduction
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What does stimulation of GI/GU muscarinic receptors by ACh cause? | increased secretions, increased GI motility, PONV
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What does stimulation of pulmonary muscarinic receptors by ACh cause? | bronchoconstriction and increased secretions
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What does stimulation of opthalmic muscarinic receptors by ACh cause? | miosis (pupillary constriction), farsightedness, decreased intraocular pressure
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What is an unlikely side effect of stimulation of muscarinic receptors that one should be mindful of in patients with myotonia, muscular dystrophies, spinal cord transection or burns? | contractions and fasiculations
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When does cholinergic crisis occur? | when there is an overstimulation of both nicotinic and muscarinic receptors due to increased amounts of ACh at the NMJ
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What are the muscarinic symptoms associated with cholinergic crisis? | miosis, inability to focus vision, salivation, bronchoconstriction, bradycardia, abdominal cramps, loss of control of bowel and bladder
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What are the nicotinic symptoms associated with cholinergic crisis? | weakness ranging to paralysis
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What are the CNS symptoms associated with cholinergic crisis? | confusion, ataxia, coma, respiratory depression
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What is the usual cause of cholinergic crisis? | overdose of anticholinesterase drugs, nerve gas exposure, organophosphate insecticide exposure
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What are the treatments for cholinergic crisis? | atropine, Pralidoxime (2-PAM, used in military settings), ventilatory support, control of seizures and other symptoms
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What is the rational for pretreating patients with anticholinergic drugs prior to administration of anticholinesterase drugs? | The effects of anticholinesterase are not limited to the NMJ. Anticholinergic drugs block the undesirable muscarinic effects without having an effect on the nicotinic effects in the NMJ.
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What is the chemical structure of atropine and what implications does it have? | tertiary ammonium, so its lipid soluble = crosses the blood brain barrier and can make patients crazy
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What is the dose of atropine? | 0.03 mg/kg
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What is the onset of atropine? | 1 minute
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You want to see an increase in __________ after giving atropine and before you give anticholinesterase (reversal agent) | heart rate
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Why is atropine the best choice for prevention of vagal response? | blocks the effect of ACh on the SA node, which shortens the PR interval
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Atropine and Glycopyrrolate cause relaxation of _______ ________ which could cause an increased risk of aspiration | esophageal sphincter
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What is the dose of Glycopyrrolate (Robinul)? | 0.015 mg/kg
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What is the onset of Glycopyrrolate (Robinul)? | 2 - 3 minutes
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What is the chemical structure of Glycopyrrolate (Robinul) and what implications does this have? | quaternary ammonium; lipid insoluble so cannot cross blood brain barrier = no CNS effects
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What is the dose of Scopolamine? | 0.4 mg IV/IM
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What is the onset of Scopolamine? | 10 minutes (IV) and 30 - 60 minutes (IM)
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What is the chemical structure of Scopolamine and how does this affect its clinical use? | tertiary amine; crosses blood brain barrier so sedative and amnestic effects, also treats PONV and has antisialagogue effects
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Rank the three anticholinergic agents in terms of usefulness for antisialagogue effects | scopolamine > glycopyrrolate > atropine
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Rank the anticholinergic agents in terms of usefulness for treatment of bradycardia | atropine > glycopyrrolate > scopolamine
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Rank the anticholinergic agents in terms of usefulness for treatment of sedative/CNS effects | scopolamine > atropine
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What determines the choice of which anticholinergic to administer with which anticholinesterase? | the speed of onset
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Which anticholinergic is used as pretreatment for Edrophonium? | Atropine
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Which anticholinergic is used as pretreatment for Neostigmine? | Glycopyrrolate (Robinul)
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What are the symptoms of Central Anticholinergic Syndrome? | restlessness and hallucinations>>>somnolence and unconsciousness, dry mouth, blurred vision, tachycardia, dilation of cutaneous vessels, increased temperature, sensitivity to light
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What is the treatment for Central Anticholinergic Syndrome (post op delirium)? | Physostigmine (Antilirium) 0.015 - 0.06 mg/kg
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What is the mechanism of action of Sugammadex (Org 25969)? | encapsulates steroidal NMB and forms a stable complex, preventing the action of the NMB on the NMJ
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Sugammadex is NOT an _____________ and therefore does NOT require an _____________ for pretreatment. | anticholinesterase
anticholinergic
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Sugammadex was produced specifically for the NMB __________ and makes this drug a __________ duration NMB for difficult airway cases. | Rocuronium
short
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Why is the FDA still approving the use of Sugammadex in the US, despite its widespread use in the UK? | it is thought to have a inhibitory effect on the immune system
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Created by:
Mary Beth
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