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24 Cards in this Set
- Front
- Back
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where is acetylcholine synthesized and by which enzyme?
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in the nerve terminals, by choline acetyltransferase ( joins acetylcoenzyme A and choline)
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How is acetylcholine metabolized?
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hydrolysis by acetylcholinesterase into acetate and choline
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where are the acetylcholine receptors found?
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entire paracsympathetic nervous system, parts of the sympathetic nervous system ( sympathetic ganglions, and adrenal medulla and some sweat glands), some CNS, skeletal muscle
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what are the two types of cholinergic receptors?
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Muscarinic and nicotinic
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where are the muscarinic receptors found?
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endo organ effector cells in bronchial smooth muscle, salivary glands, and the SA node, some CNS
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where are the nicotinic receptors found?
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skeletal muscle and the autonomic ganglia
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what is the goal of reversal of neuromuscular blockade?
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Maximize nicotinic transmission and minimize muscarinic side effects
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what is the function of cholinesterase inhibitors?
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inactivate acetylcholinesterase by reversibly binding to the enzyme and indirectly increasing the amount of acetylcholine to compete w/ nondepolarizers.
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What are organophosphates?
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cholinesterase inhibitors that for stable, irreversible bonds w/ the enzyme
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Effect of acetylcholinesterase blockers on succinylcholine?
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Potentiation of block, due to and increase of acetylcholine and inhibition of pseydocholinesterase activity .
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what is the effect of cholinesterase inhibitors at sites other than skeletal muscle?
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CV- bradycardia
Pulmonary - bronchospasm, increased secretions GI - diarrhea, increased peristalsis CNS - diffuse excitation GU - increased bladder tone Ophto - pupillary constriction |
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How many min after a palpable post0tetanic twitch does the first TOF appear for vec? for panc?
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about 10 min for vec and about 40 for panc
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Neostigmine, structure
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carbamate moiety and a quaternary ammonium group, enables covalent bonding
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Does Neostigmine pass through the blood brain barrier?
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No
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Neostigmine dosage?
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0.08 mg/ kg ( up to 5 mg in adults)
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When does the effect of neostigmine peak?
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at 10 - 15 min
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Does neostigmine cross the placenta?
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Yes, can cause fetal bradycardia. For this reason it's better to reverse w/ atropine if using neo
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How potent is pyridostimine vs. neostigmine?
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Pyridostigmine is about 20% as potent as neostigmine
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dosage for pyridostimine?
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0.4 mg/kg (a total of 20 mg in adults)
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Onset of action for pyridostimine
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slower than neostigmine, about 10-20 min.
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Edrophonium, how does it bind to acetylcholinesterase?
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Non-covalent bonding, shorter acting
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Edrophonium dosage
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0.5-1 mg/kg , it's less than 10 % as potent as neostigmine
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Edrophonium onset of action
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rapid, 1-2 min
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what is physostigmine commonly used for?
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treatment of central anticholinergic toxicity, because it freely passes the blood brain barrier
prevention of post-op shivering reversal of benzo-induced delirium |
