CHAPTER 4: INDIRECT ACTING CHOLINERGIC AGONISTS Flashcards

1
Q

how do Indirect Acting Cholinergic agonists work?

A

they act on the ENZYME

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2
Q

what enzyme does indirect chol agonist act on

A

cholinesterases that act indirectly on PNS

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3
Q

indirect chol agonists- response in which receptors

A

muscarinic and nicotinic in ANS and brain

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4
Q

what are the indirect-acting cholinergic REVERSIBLE agonists

A

Edrophonium, physostigmine, neostigmine, donepezil, rivastigmine, galantamine

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5
Q

indirect chol agonist- Edrophonium (reversible)
- what does it bind to
- duration of action

A

quarternary ammonium comound that binds reversibly to the active site of AChE, prevents hydrolysis of ACh
-RAPID duration of actions (10-20 mins)

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6
Q

edrophonium- therapeutic action

A

rapid inc muscle strength

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7
Q

edrophonium- therapeutic uses/indications

A

diagnose myasthenia gravis

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8
Q

edrophonium- adverse effects
-what drug counteracts?

A

cholinergic crisis with excess of the drug, then you need withdrawal and use ATROPINE TO COUNTERACT

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9
Q

what is Myasthenia Gravis?

A

chronic muscular disease caused by a defect in neuromuscular transmission
-autoimmune disease, so patients make antibodies to ACh receptions, gradually destroying them

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10
Q

myasthenia gravis symptoms
-myasthenic crises

A

progressive weakness, lack of muscle control

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11
Q

myasthenic crisis vs. cholinergic crisis

A

myasthenic: extreme muscle weakness, difficult respiration, NEED INC DOSE

cholinergic: progressive muscle weakness, difficult respiration while ACh accumulates at receptors, reduced impulse transmission, WITHDRAWAL OF DRUG NEEDED

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12
Q

edrophonium for crisises

A

used as a diagnostic agent to treat or cause adverse effects

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13
Q

edrophonium in myasthenic crisis

A

patient improves immediately after injection

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14
Q

edrophonium in cholinergic crisis

A

patient gets WORSE, drug toxicity (cholinergic crisis), atropine alleviates parasymp reactions to this cholinergic drug

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15
Q

Indirect acting reversible- Physostigmine
-action
-duration of action

A

binds reversibly to AChE prevent Ach degradation
-duration of action 2-4 HOURS
-can enter CNS
tertiary amine (not charged)

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16
Q

Physostigmine- therapeutic effects

A

potential cholinergic activity throughout body
- miosis
-contraction of visceral smooth muscle
-skeletal muscle twitching

17
Q

Physostigmine- therapeutic uses/indications

A

optho for glaucoma
treating overdose of anticholinergic drugs

18
Q

Physostigmine- adverse effects

A

convulsions, bradycardia, fall in cardiac output

19
Q

Indirect acting chol ago reversible- Neostigmine
-action
duration of action

A

-bind to AChE stop degrading ACh
-duration of action 30min-2hours
-synthetic and CHARGED compound (N+)

20
Q

Neostigmine- therapeutic effects

A

effect of skeletal muscle greater than physostigmine

21
Q

Neostigmine- therapeutic uses/indications

A

antidote for tubocurarine (NMB)
treats myasthenia gravis

22
Q

Neostigmine- adverse effects

A

general cholinergic stimulation (salivation, flushing, nausea, diarrhea, bronchospasm)
NO CNS SIDE EFFECTS (bc its charged, doesn’t cross BBB)

23
Q

Indirect chol ago reversible- Donepezil, Rivastigmine, Galantamine

A

deficiency of cholinergic neuron in ALZHEIMER’S DISEASE
-anticholinesterases as remedies for loss of cognitive functions
-delay of progression

24
Q

what are the IRREVERSIBLE indirect-acting cholinergic agonists?

A

echothiophate and pralidoxime

25
indirect cholinergic agonist irreversible- Echothiophate -purpose -duration of action
phosphate compound that INACTIVATES AChE permanently when covalently bonded -duration of action 1 WEEK
26
echothiophate- therapeutic actions
cholinergic stimulation, paralysis of motor function, convulsions -MIOSIS
27
echothiophate- therapeutic use/indication
open-angle glaucoma
28
echothiophate- adverse effects
risk of causing cataracts limit use
29
30
nerve gas is
an irreversible acetylcholinesterase inhibitor (echothiophate)
31
nerve gas causes
muscle paralysis, stop breathing, death
32
antidote for nerve gas- irreversible indirect-acting cholinergic agonists
pralidoxime
33
pralidoxime also used with...
atropine since it can cross the BBB, its the antidote for CNS