Muscle Paralytics and activators

Question 1

What effect will anticholinesterases have on skeletal muscle? WHat disease are they used in?

Answer 1

They will increase skeletal muscle contraction by reducing ACh degradation.

used for rmyasthenia gravis

Question 2

What are the three acetylcholinesterases that we talked about? Which is used most often? Which is used as a diagnostic?

Answer 2

Neostigmine

Pyridostigmine (used more often)

Edrophonium (used to test)

Question 3

What is used to treat muscle spasms by blocking acetylcholine release?

Answer 3

botulinum toxin

Question 4

Which anticholinesterase has been used to prevent nerve gas action?

Answer 4

pyridostigmine

Question 5

What will happen in an edrophonium test if the patient has myasthenia gravis? How about if they have a cholinergic crisis?

Answer 5

MG = muscle strength will increase

CHolinergic crisis = muscle strength will decrease

Question 6

What are the anticholinesterase side effects?

Answer 6

SLUDGE

sweating

lacrimation

urination

diarrhea

GI distress

Emesis

Question 7

WHat are the two competitive ACh blockers we need to know about?

Answer 7

d-tubocurarine (from curare)

mivacurium

Question 8

What is the depolarizing agent that works as a neuromuscular blocker?

Answer 8

Succinylcholine

Question 9

Which can be reversed: the competitive blockers or the depolarizing agents? How?

Answer 9

THe competitive blockers can be reversed by giving an anticholinesterase

the depolarizing agent can’t be reversed -you have to just wait until the body works it out

Question 10

Specifically what does succinylcholine do?

Answer 10

it depolarizes the end plate of the muslcle by causing chronic Na+ influx. This results in continuous depolarization sot aht the receptor can eventually no longer fire

You’ll sed fasciculations preceding flaccid paralysis

Question 11

Why wouldn’t you want to give succinylcholine to a burn patient?

Answer 11

burned skin has an increase in nicotiinc receptors, so if you give them succinylcholine they will release too much K+

Question 12

Besides anticholinesterases, what can you give to slightly reverse a competitive blockade using either tubocurarine or mivacurium?

Answer 12

epinephrine or norepinephrine

Question 13

What are some of the toxic effects of the neuromuscular plockers (paralytics)?

Answer 13

apnea (paralysis of diaphragm)

hitamine release in anaphylaxis

CV collapse

malignant hyperhtermia (especially with succinylcholine)

Question 14

What is the treatment for malignant hyperthermia? How does it work?

Answer 14

it blocks calcium release from the sarcoplasmic reticulum by blocking the ryanodine receptor

Question 15

All paralytics are metabolized by the kidneys except….

Answer 15

atracurium - so give this one for people in renal failure

Question 16

What structure do the competitive inhibitors have?

Answer 16

quaternary ammonium ion structures

Question 17

Are the competitive inhibitors have short or long duration?

Answer 17

short - which is nice, because you can just stop infusing them when you don’t need their action anymore

Question 18

Vecuronium is another competitive inhibitor paralytic like tubocurararine, but with what added benefits?

Answer 18

it doesn’t block the vagal effects on the heart

won’t release histamine

Question 19

Which patients will be somewhat resistant to the effects of succinylcholine? WHy?

Answer 19

People with myasthenia gravis - they have fewer nicotinic receptors to block

Question 20

How is the action of succinylcholine stopped?

Answer 20

degradation by a native enzyme - butyrylcholinesterase

Question 21

Because of its rapid action, succinylcholine is preferred for what procedure?

Answer 21

intubation

Question 22

WHat is the most lethal toxin known?

Answer 22

botulinum toxin

worrisome because we only have antisera against 3 out of 8 types