Muscle Relaxants Flashcards

1
Q

What are the two groups of skeletal muscle relaxants?

A

1) Muscle Paralyzers AKA neuromuscular blocking agents or neuromuscular blockers
2) Spasmolytics- reduce muscle spasm

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2
Q

When are neuromuscular blocking agents (muscle paralyzers) used?

A
  • when we want muscle paralysis

- surgery or in ICU on ventilator

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3
Q

MOA of neuromuscular blocking agents

A

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

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4
Q

Do neuromuscular blocking agents have an effect of the brain?

A

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

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5
Q

Route of administration for neuromuscular blocking agents

A

IV

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6
Q

Can neuromusclar blocking agens get into the CNS

A

no they are polar

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7
Q

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

A

1) Nondepolarizing blocade- prevent accsess of transmitter and prevent depolarization
2) Depolarizing blockade- cause depolarization by producing excess acetylcholine

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8
Q

List the Nondepolarizing Neuromuscular Blockers

A
  • Curare- first discovered, darts
  • curium

pancuronium- long acting

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9
Q

MOA of nondepolarizing blockers

A

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

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10
Q

How do you reverse nondepolarizing blockers?

A

acetycholine esterase- floods synapse with acetylcholine

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11
Q

What is the progression of paralysis with nondepolarizing neuromuscular blockers?

A

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

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12
Q

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

A

succinycholine

SHORT 5-10 minutes

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13
Q

MOA of succinycholine (depolarizing neuromuscular blocker)

A

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

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14
Q

CVS effects of depolarizing neuromuscular blockers are

A

1) hypotension from histamine release

2) arythmias

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15
Q

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

A

anti histamines

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16
Q

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

A

-burns
-nerve damage
-neuromuscular dz
trauma

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17
Q

Inhaled anesthetics combined with nondepolarizing neuromuscular blockers may cause

A

increased blockein

malignant hyperthermia

18
Q

What do you treat malignant hyperthermia with?

A

Dantrolene

19
Q

What are three clinical uses of neuromuscular blockers?

A

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

20
Q

Neuromuscular blockers in surgical relaxation

A
  • when you cut into muscle it contracts

- intra-abdominal and intra-thoracic surgeries

21
Q

How do you monitor neuromuscular blockade during surgery?

A

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

22
Q

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

A

neostigmine

pyridostigmine

23
Q

Neuromuscular blockers used in ventilation

A

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

24
Q

Neuromuscular blockers used in intubation

A

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

25
Q

Muscle Spasticity

A

increase in tonic stretch reflexes and flexor muscle spasm

26
Q

Spasmolytics

A

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

bring relief to muscle spasms

27
Q

What is the only spasmolytic that is not centrally acting?

A

Dantrolene (dantrium)

28
Q

Spasmolytics list

A
Dantrolene (Dantrium)
Diazepam (valium)
Baclofen (lioresal)
Tizanidine (zanaflex)
Gabapentin/pregabalin
carisoprodol (soma)
cyclobenzaprine (flexeril)
29
Q

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

A
  • benzo
  • facilitates gaba action
  • muscle spasm of any origin
  • CNS depression
30
Q

Baclofen (Lioresal)
MOA?
Risk?

A

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
Q

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

A

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
Q

Gabapentin/Pregabalin used in what Dz?

A

MS

33
Q

Gabapentin/ Pregabalin dosage?

A

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

34
Q

Dantrolene (Dantrium)
MOA?
clinical use?

A

MOA: works on muscle fibers and prevents release of calcium

clinical use: spasms from spinal cord or CNS, & malignant hyper thermia

35
Q

ADR of Dantrolene (Dantrium)

A
  • true muscle weakness

- symptomatic hepatits

36
Q

Malignant hyperthermia

A

-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
Q

What is the treatment of malignant hyperthermia?

A

Dantrolene

38
Q

Other drugs grouped together that treat muscle spasms (list)

A
Cyclobenzaprine (Flexeril), the protoype
Orphenadrine (Norflex)
Carisoprodol (Soma)- abused
Metaxalone (Skelaxin)
Methocarbamol (Robaxin)
39
Q

What does the Misc group of spasmotics do?

When do you not use them?

ADR?

A

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

40
Q

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

A
  • Diazepam
  • Baclofen
  • Tizanidine
  • Dantrolene
41
Q

List of musclerelaxants used when pain is caused muscle spasm

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