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56 Cards in this Set
- Front
- Back
Which group of cholinergic drugs acts on both muscarinic & nicotinic receptors to inactivate parasympathetic response? |
cholinergic antagonists/parasympathetics
= inactivate parasympathetic Ach (at nicotinic ganglion & NMJ receptors)
(cholinomimetics/parasympathomimetics act like parasympathetic Ach) |
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___________ are cholinomimetics that act DIRECTLY on muscarinic receptors
____________ are cholinomimetics that act INDIRECTLY by inhibiting Ach breakdown at synapse |
Cholinergic agonists are direct
acetyl cholinesterase inhibitors are indirect |
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What are the 3 categories of cholinergic agonists? |
Choline esters |
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What is an example of a choline ester?
|
Bethanechol |
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What is an example of an M3 specific agonist? |
Cevimeline
|
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What is an example of a natural alkaloid?
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Pilocarpine
|
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Why isn't Ach used clinically?
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As soon as you ingest it, it gets broken down & it is very nonspecific |
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What is the main difference between Ach and metacholine? |
Metacholine acts predominantly on muscarinic receptors (also a little less hydrolyzed by acetylcholinesterase, breaks down slower) |
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Carbachol is used in treatment of what, seldomly? |
Glaucoma
(has a long life but isn't specific) |
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Bethanechol is used in treatment of what? What receptors is it specific for? |
Bladder and GI hypotonia muscarinic (agonist) |
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Pilocarpine is used in treatment of what? What receptors is it specific for? |
Glaucoma muscarinic (agonist) |
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Cevimeline is used in treatment of what? What receptor is it specific for? |
dry mouth in patients with Sjogren's Syndrome muscarinic (agonist) |
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Bethanechol |
1. Clinical Uses: (restarts parasympathetics) |
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Pilocarpine |
1. Clinical Uses: |
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Cevimeline
1. Clinical Uses 2. MOA |
Cevimeline |
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which of the following is PREFFERED for Xerostomia treatment?
Piocarpine Bethanechol Cevimeline |
Cevimeline *1st line
(then pilocarpine, lastly bethanechol) |
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What are some side effects of muscarinic agonists (aka cholinergic agonists)? |
- Diarrhea |
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Why is asthma a contraindication for muscarinic agonists? |
Muscarinic agonists can cause bronchoconstriction and increase mucous secretion (further inhibits breathing) |
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Why is heart disease a contraindication for muscarinic agonists?
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Slowing conduction of cardiac action potential through AV node may precipitate arrhythmias. |
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What are 2 examples of pseudo cholinesterases? |
Plasma cholinesterase
("Real" AChE degrades Ach ONLY) |
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What are potential sites of action for Ach esterase inhibitors? |
- At all effector organs innervated by parasympathetic system such Eye, GI, urinary bladder
Fxn to prolong Ach action by inhibiting breakdown |
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What is a short (~10 min), reversible AChE inhibitor?
|
Edrophonium
|
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What are some intermediate, reversible AChE inhibitors? |
- Physostigmine |
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What are some synthetic organophosphate, irreversible (long) AChE inhibitors? |
- Ecothiophate
|
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What are some nerve gas, irreversible (long) AChE inhibitors?
|
- Sarin
*all long change enzyme structure = poison |
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What AChE inhibitors are used for myasthenia gravis? |
- Edrophonium (diagnostic test only, last 10 min)
(all reversible) (Myasthenia gravis- Abs attack cholinergic receptors, less receptors, need Ach to last longer) |
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What AChE inhibitor is used for hypotonia of bladder and GI? |
Physostigmine |
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What AChE inhibitors are used for Glaucoma? |
- Physostigmine |
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What AChE inhibitors are used for Alzheimers?
|
- Donepezil |
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Neostigmine |
1. Clinical Uses: |
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What are some warning signs that a patient will go into cholinergic crisis? |
excessive drooling, sweating (parasympathetic response)
followed by complete atonia = cholinergic crisis |
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Physostigmine |
1. Clinical Uses: |
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a) How might someone get organophosphate poisoning? |
a) Many insecticides and pesticides contain cmpds that are long acting AChE inhibitors. Accidental or intentional poisoning gives rise to a slew of symptoms that involve activation of muscarinic & nicotinic receptors. Also from nerve gases! |
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How is organophosphate poisoning treated prophylactically? |
Pyridostigmine (during chemical warfare)
-takes up majority of receptors so that they are already occupied (decr. severity) |
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How is organophosphate poisoning treated post-exposure? |
High doses of muscarinic antagonist atropine or Scopolamine followed by an injection of Pralidoxime can reverse the effects of poisoning |
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What are 2 subcategories of muscarinic receptor antagonists (these do the opposite of AChE inhiibitors)? |
Belladona Alkaloids
Synthetic & Semi-synthetic Derivatives |
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What are examples of Belladona alkaloids? |
Atropine* |
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What are some commonly used examples of synthetic and semi-synthetic derivatives (muscarinic receptor antagonists)? |
Ipratropium |
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Atropine |
1. Clinical Uses: |
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Scopolamine |
1. Clinical Uses |
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Ipratropium Bromide |
1. Clinical Uses: (anything -IUM doesnt cross BBB) |
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At very low doses, what is unique about atropine? |
It causes slight cardiac slowing, because every nerve terminal regulates its own release. The M2 presynaptic reduces release of ACh. |
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Tiotropium Bromide |
- Clinical uses: COPD and Asthma
- Much more selective action at the bronchioles - Greater affinity for M3 vs M2 |
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Tolterodine
1. Clinical Uses 2. MOA |
1. Clinical Uses: |
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What is a contraindication to M3 antagonists?
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Slows Voiding: Not appropriate in individuals with urinary retention (eg Benign prostatic Hyperplasia (BPH) |
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What makes tolterodine different from the other M3 antagonists (Fesoterodine, |
The others don't favor M3 much more than M2 |
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What are some contraindications to muscarinic antagonists?
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- Glaucoma (b/c of mydriasis) |
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T/F |
True! |
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What are some non-depolarizing NMJ blockers? |
Atracurium* |
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What is an example of a depolarizing NMJ blocker?
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Succinyl choline
(NMJ blockers (both kinds)= muscle relaxers) |
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What is the MOA of non-depolarizing NMJ blockers?
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They block the nicotinic receptor at the NMJ & prevent the actions of acetylcholine. |
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What is the molecular structure of succinylcholine? |
2 ACh molecules linked end to end |
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What is the MOA for succinyl choline? (Both phase 1 and phase 2) |
PHASE 1: |
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What are side effects of succinyl choline?
|
- Muscle pain postoperatively (damaged muscle due to fasciculations (?)) |
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Q: Which of the following drugs have the potential for greater CNS side effects at therapeutic doses?
Atropine Scopolamine Tiotropium Tolterodine |
A: Scopolamine
(atropine also have CNS effects but NOT at therapeutic doses, other 2 do not) |
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Q: Which of the following is the shortest acting AChE inhibitor? Ecothiphate Edrophonium Physostigmine Neostigmine Pyridostigmine |
Edrophonium!
(only short acting one, less than 10 min) |