Cholinergics II and Muscle Blockers Flashcards Preview

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Flashcards in Cholinergics II and Muscle Blockers Deck (36)
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1

What is the mechanism of action

of Indirect Cholinergic Agonists

Block acetylcholinesterase thereby increasing the amount of Ach in the synapse

 

2

Why are anticholinesterases called "Indirect" Cholinergic Agonists? 

They do not directly activate the Cholinergic receptors,

but rather,

they increase the actions of endogenous Ach

3

What is the effect of Indirect Cholinergic Agonists on vascular smooth muscle (and blood pressure)? 

No effect

because they increase the amount of

endogenous Ach in the synapse

and there is no endogenous Ach

at smooth muscles because there is no innervation! 

4

How much do Indirect Cholinergic Agonists 

affect muscarinic and nicotinic receptors? 

At low-moderate doses they affect muscarinic.

At high concentration they activate nicotinic receptors 

and thus muscle contractions, fasciulations and convulsions

5

What are other names for "Indirect Cholinergic Agonists?" 

Indirect Cholinomimetics

 

Anticholinesterases

6

What are the important Indirect Cholinergic Agonists we need to know? 

Neostigmine

Physostigmine

Donepesil

Sarin

7

Name the durations of actions of: 

Physostigmine

Neostigmine

Donepezil

Sarin

Physostigmine: .5 - 2 hours

Neostigmine: .5 - 2 hours

Donepezil: 24 hours

Sarin: > 4 days

8

If you needed to prescribe a short-acting anticholinesterase, what would your choices be? 

Neostigmine

Physostigmine

9

What do the key indirect cholinomimetics treat? 

Neostigmine

Physostigmine

Donepezil

Neostigmine: Myasthenia Gravis, Paralytic Ileus

Physostigmine: Glaucoma (miotic)

Donepezil: Alzheimers

10

What Anticholinesterase would you prescribe to treat Alzheimer's 

Donepezil

11

What anticholinersterase would you prescribe for a patient with glaucoma

Physostigmine

12

What Indirect Cholinomimetic would you prescribe to treat Myasthenia Gravis or Paralysic Ileus? 

Neostigmine

13

What Anticholinesterase

is used to diagnose Myasthenia Gravis?

Why is this the best anticholinesterase for this purpose? 

Edrophonium

Because its Duration of action is 5-15 minutes

14

Which reversible anticholinesterase

can cross the blood brain barrier? 

Physostigmine

Donepezil

(Neostigmine cannot cross BBB)

15

If you are prescirbing Neostigmine to treat Myasthenis Gravis, what do you do about

unwanted muscarinic receptor activiation

Give Atropine to control these side effects

16

What anticholineresterase can reverse the paralytic effects of Vecuronium? 

(What is the "antidote")

Neostigmine

17

Your patient just got out of abdominal surgery

and now has a paralytic ileus.

How do you treat this? 

Neostigmine

18

How does Donepezil treat Alzheimer's Disease? 

Alzheimer's patients have decreased cholinergic function

due to cholinergic neuron damage and death,

leading  to problems with memory and cognition. 

Donepezil crosses the BBB

decreases aceylcholinesterase by 40%

and thereby increases ACh at CNS synapses. 

 

HOWEVER: does not prevent progression

19

How do Sarin

and other organophosphates like Parathion

get into the body? 

They are very volatile liquids and

are lipid soluble and enter through any exposure to skin

20

What are the initial symptoms

of organophosphate poisoning

(like Sarin or Parathion)

SLUDGE

Salivation

Lacrimation

Urination

Defecation

GI Distress

Emesis

Basically if you have a patient who has stuff pouring out of every orifice, think organophosphate poisoning! 

21

What are late symptoms of organophosphate poisoning? 

bronchodilation, bradycardia, hypotension, pulmonary edema

 twitching

respiratory paralysis (skeletal muscles: diaphragm, etc)

Ataxia, confusion, convulsions, coma, death

22

A 25 year old landscaper is brought in on an ambulance.

He loos  very sick, vomiting, drooling, with watery eyes. 

He smells terrible and the EMT says that he urinated and defecated in his pants and was moaning about his stomach hurting. 

What are you thinking? 

Organophosphate poisoning

23

What is the antidote to nerve gas/Sarin gas? 

Atropine to block excess muscarinic activation

plus

Pralidoxime to reactivate acetylcholinesterase.

24

What is the only available ganglionic blocker and what is it used to treat and why? 

Trimethaphan

Used to treat acute dissecting aortic aneurysm

 

Used to allow physician to completely control BP

by blocking physiologic reflexes

25

Does Trymethaphan control the

sympathetic or

parasympathetic systems? 

Both

because it blocks gangionic nicotinic receptors. 

But it has no effect on skeletal muscles

26

What are skeletal muscle blockers and how are they used? 

Skeletal Muscle Nicotinic Antagonists

used to temporarily paralyze muscles for surgery

27

What are the two types

of skeletal muscle blockers and how to they work

Depolarizing: agonist that opens channel gate,

but then blocks the channel

Nondepolarizing: Prevents the channel gate from opening, thus a competitive antagonist

28

Is vecuronium a nondepolarizing or depolarizing skeletal muscle blocker? 

What is it used for? 

Nondepolarizing

Used to paralyze skeletal muscles for 1-1.5 hrs during surgury. 

Highly charged. 

Does not cross BBB.

NOT an anesthetic!!!! 

29

Your patient is out of surgery

and you want to reverse the effect of Vercuronium.

What can you use? 

Neostigmine

increases Ach levels

and overcomes the competitive blockade

at the nicotinic receptors. 

Atropine often added as well. 

30

Is succinylcholine

a depolarizing or nondepolarizing muscle blocker? 

What is it used for? 

Depolarizing

Used in preparation for endrotracheal intubation

because it has rapid onset and is short acting.