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Flashcards in Muscle Relaxants Deck (41):
1

What are the two groups of skeletal muscle relaxants?

1) Muscle Paralyzers AKA neuromuscular blocking agents or neuromuscular blockers

2) Spasmolytics- reduce muscle spasm

2

When are neuromuscular blocking agents (muscle paralyzers) used?

-when we want muscle paralysis
- surgery or in ICU on ventilator

3

MOA of neuromuscular blocking agents

Block transmission of signal from the nerve to the muscle at the junction where the nerve meets the muscle (AKA neuromuscular endplate)

4

Do neuromuscular blocking agents have an effect of the brain?

NO. The patient is aware they can't move if they are awake

5

Route of administration for neuromuscular blocking agents

IV

6

Can neuromusclar blocking agens get into the CNS

no they are polar

7

What are the two methods the neuromuscular blocking group can block the neuromuscular jxn?

1) Nondepolarizing blocade- prevent accsess of transmitter and prevent depolarization

2) Depolarizing blockade- cause depolarization by producing excess acetylcholine

8

List the Nondepolarizing Neuromuscular Blockers

- Curare- first discovered, darts

-curium

pancuronium- long acting

9

MOA of nondepolarizing blockers

competitive antagonists to acetylcholine (nicotinic subtype) receptor at the neuromuscular junction but does not activate receptor

10

How do you reverse nondepolarizing blockers?

acetycholine esterase- floods synapse with acetylcholine

11

What is the progression of paralysis with nondepolarizing neuromuscular blockers?

motor weakness - skeltal muscles flacid- larger muscles paralyzed last - diaphragm very last

12

What is the only depolarizing neuromuscular blocker? how long does it last?

succinycholine

SHORT 5-10 minutes

13

MOA of succinycholine (depolarizing neuromuscular blocker)

Succinylcholine binds & activates the nicotinic receptor once causing one transmission of an impulse to the muscle.
Then it doesn't transmit anymore and doesn’t leave the receptor either.

muscle stays in depolarized state

14

CVS effects of depolarizing neuromuscular blockers are

1) hypotension from histamine release
2) arythmias

15

what can you give to prevent hypotension with depolarizing neuromuscular blockers?

anti histamines

16

What patient dispositions leads to hyperkalemia in they are given depolarizing neuromuscular blockers?

-burns
-nerve damage
-neuromuscular dz
trauma

17

Inhaled anesthetics combined with nondepolarizing neuromuscular blockers may cause

increased blockein
malignant hyperthermia

18

What do you treat malignant hyperthermia with?

Dantrolene

19

What are three clinical uses of neuromuscular blockers?

1) Surgical relaxation
2) Control of ventilation
3) Tracheal intubation

20

Neuromuscular blockers in surgical relaxation

-when you cut into muscle it contracts
-intra-abdominal and intra-thoracic surgeries

21

How do you monitor neuromuscular blockade during surgery?

transdermal electrical stimulation of peripheral nerves (hands or face) and record the evoked contractions

22

What are acetycholine esterase inhibitors you can give pts. to undoe nondepolarizing neuromuscular blocers?

neostigmine
pyridostigmine

23

Neuromuscular blockers used in ventilation

get better control of ventilation and better oxygen exchange if paralyzed as opposed to just sedated

24

Neuromuscular blockers used in intubation

relaxes upper airway muscles and can make it easier to place tracheal tube.

25

Muscle Spasticity

increase in tonic stretch reflexes and flexor muscle spasm

26

Spasmolytics

modify the stretch reflex arc or interfering directly with the skeletal muscle

bring relief to muscle spasms

27

What is the only spasmolytic that is not centrally acting?

Dantrolene (dantrium)

28

Spasmolytics list

Dantrolene (Dantrium)
Diazepam (valium)
Baclofen (lioresal)
Tizanidine (zanaflex)
Gabapentin/pregabalin
carisoprodol (soma)
cyclobenzaprine (flexeril)

29

Diazepam (valium)
Class?
MOA?
Addresses muscle spasms caused by what?

-benzo
-facilitates gaba action
- muscle spasm of any origin
-CNS depression

30

Baclofen (Lioresal)
MOA?
Risk?

Agonist at the GABA receptors which results in decreased release of excitatory neurotransmitters in brain & substance P

increased seizure threshold

less sedating than valium

31

Tizanidine (zanaflex)
MOA?
Addresses muscle spasms caused by what?
ADRS?

MOA: some effects as a CNS alpha 2 adrenergic agonist

clinical use: spasticity from cerebral or spinal injury

sense of weakness & loss of strength without true loss of strength

32

Gabapentin/Pregabalin used in what Dz?

MS

33

Gabapentin/ Pregabalin dosage?

800mg 4 times a day, takes a while to get up to this dose

34

Dantrolene (Dantrium)
MOA?
clinical use?

MOA: works on muscle fibers and prevents release of calcium
clinical use: spasms from spinal cord or CNS, & malignant hyper thermia

35

ADR of Dantrolene (Dantrium)

- true muscle weakness
-symptomatic hepatits

36

Malignant hyperthermia

-heritable disorder induced when given general anesthetics and succunylcholine

prolonged release of calcium from the muscle, causing massive muscle contraction, lactic acid production, fever, death

37

What is the treatment of malignant hyperthermia?

Dantrolene

38

Other drugs grouped together that treat muscle spasms (list)

Cyclobenzaprine (Flexeril), the protoype
Orphenadrine (Norflex)
Carisoprodol (Soma)- abused
Metaxalone (Skelaxin)
Methocarbamol (Robaxin)

39

What does the Misc group of spasmotics do?

When do you not use them?

ADR?

treat muscle spasm from trauma
DO NOT USE FOR CNS OR SPINAL INJURIES
STONGLY ANTICHLONINERGIC- Hallucinations

40

List of Rxs muscle relaxants used in true muscle spasms from neurologic injury

-Diazepam
-Baclofen
-Tizanidine
-Dantrolene

41

List of musclerelaxants used when pain is caused muscle spasm

Cyclobenzaprine (Flexeril), the protoype
Orphenadrine (Norflex)
Carisoprodol (Soma)- abused
Metaxalone (Skelaxin)
Methocarbamol (Robaxin)