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22 Cards in this Set
- Front
- Back
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Cholinergic Drugs
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-activate M1, M2, M3
-some choline esters activate nictotinic receptors (prolonged activations =depolarization blockade) -effects equiv to postganglionic PNS impulses |
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effects of choline esters
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-decreased: HR, atrial refractoriness, conuction and automacity of AV node, NE release increased: av node refractoriness
-vasodilation, smooth muscle contraction, sphincter relaxation, mild stim of insulin release, erection, increased secretions, cyclospasm and widening of spaces within trabecular networks |
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pharmacokinteics of choline esters
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-low oral availability
-dist to peripheral tissues -Ach -rapidly hydrolyzed but carbachol and bethanechol are resistant -excretion by kidney -Admin ach and carbachol -> topical instillation on the conjuctiva, bethanechol -> PO, SC |
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adverse effects of choline esters
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-locally:visual problems, irritation of conjuncttiva, iritis, cataract, retinal detachment
-systemically: nausea, bronchospasm, sweating, lacrimation, salivation, flushing and warm skin, urinary urgency, hypotension |
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contraindications of choline esters
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-locally: cataracts of hx of retinal detachment
-systemically:asthma, COPD, arrythmias, CAD, hypotension, peptic ulcer disease, GI obstructions, IBS, IBD, peritonitis, urinary tract obstruction, hyperthyroidism |
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Pilocarpine
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-cholinergic natural alkaloid
-tertiary amine contained in plants of the genus Pilocarpus |
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Muscarine
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-cholinergic natural alkaloid
-quaternary ammonium comppound contained mainly in mushrooms of the genus Inocybe and Clitocybe |
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cholinergic natural alkaloids
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-activate M1, M2, M3
-peripheral effects like choline esters, central effects include arousal, excitation, headache, and tremors -adverse effects: like choline esters, poisoning (shrooming) = mycetism - effects of a trip/sedative -tx: pilocarpine-open-angle glaucoma, xerostomia muscarine - none |
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Edrophonium
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-cholinesterase reversible inhibitor
-binds to active site -lasts 2-10 min |
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Carbamates
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-cholinesterase reversible inhibitor
-under 2 step hydrolysis with a prolonged second step lasts 1-6 hours -can directly activate nicotinic receptors |
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Organophospates
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-cholinesterase irrversible inhibitor
-bind to esteratic site -aging=loss of alkyl group -> more stable bond |
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effects of cholinesterase inhibitors
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-moderate doses: increased alertness, stimulation of various central activities, bradycardia, increased strength of muscle contraction
-high doses:confusion, ataxia, loss of reflexes, generalized convulsions, coma, central respiratory paralysis, marked brady and hypotensions, fasciculations, and neuromuscular blockade |
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pharmacokinteics of cholinesterase inhibitors
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-tertiary amines _>good oral bioavail, enter CNS
-quaternary compounds-> low oral bioavail, dist to periphery, -organophosphates -> very good oral bioavail, dist in all tissues, hydrolyzed by paraoxonases -carbamates hydrolyzed by plasma esterases -excreted by kidney |
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toxicity of cholinesterase inhibitors
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-same as cholinomimetics + fatigue, muscle cramps, and fasiculations and cataracts
-death usually from primary resp failure -tx: watch vital signs, treat convulsions with diazepam, give atropine, give cholinesterase reactivators |
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cholinesterase reactivatores
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-oximes - high affinity for phosphorous atom = regenerate enzyme as long as it didn't age
-best seen at neuromuscular junction low biovail, does not enter brain, halflife 1-1.5 hours -toxicity:muscular weakness, dizziness, headache, nausea -used to treat poisoning by organophosphate insecticides |
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therapeutic uses of cholinergic drugs
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-open angle glaucoma: reduce intraocular pressure
-myasthenia gravis: to dx (edrophonium IV) AND to tx (neostigmine) -xerostomia, postop nonobstructive ileus, postop and postpartum urinary retention, neurogenic bladder -Alzheimer's (Donepezil) selective inhib of acetylcholinesterase in brain ->slows deterioration of cog function in early stages |
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Cholinomimetrics
-drugs for glaucoma |
-carbachol, pilocarpine, physostigmine
-increase aq humor outflow |
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non-selective alpha agonists
-drugs for glaucoma |
-epinephrine
-decrease aq humor production -increase aq humor outflow |
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selective alpha-2 agonist
-drugs for glaucoma |
-apraclonidine
-decreased aq humor production |
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beta-blockers
-drugs for glaucoma |
-timolol and betaxolol
-decreased aq humor production |
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diuretics
-drugs for glaucoma |
-acetazolamide and dorzolamide
-decrease aq humor production -mannitol -increase aq humor outflow |
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prostaglandin analogs
-drugs for glaucoma |
-lantanoprost
-increase aq humor outflow |
