skeletal muscle relaxants Flashcards Preview

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Flashcards in skeletal muscle relaxants Deck (26)
1

tubocurarine

LONG ACTING

benzylisoquinolines
non-depolarizing blocker

may release histamine - give with antihistamine

may also block nicotinic receptors in ANS and adrenal medulla -- hypotension and tachycardia

2

atracurium

INTERMED ACTING

benzylisoquinolines
non-depolarizing blocker

forms metabolite = laudanosine - may cause hypotension and seizures
(replaced by cisatracurium)

no inc in half life in pt with renal failure

3

cisatracurium

INTERMED ACTING

benzylisoquinolines
non-depolarizing blocker

forms less laudanosine and causes less histamine release

REPLACED atracurium

4

mivacurium

SHORT ACTING (only one)

benzylisoquinolines
non-depolarizing blocker

hydrolyzed by butyrylcholinesterase

5

pancuronium

LONG ACTING

ammonio steroids
non-depolarizing blocker

AE: mod tachycardia d/t blockade of M2

6

rocuronium

INTERMED ACTING

ammonio steroids
non-depolarizing blocker

most rapid == used for rapid sequence intubation

7

vecuronium

INTERMED ACTING

ammonio steroidsnon-depolarizing blocker

8

succinylcholine

only depolarizing blocker = 2 ach molecules bound

very short duration b/c of butyrylcholinesterse hydrolysis

remember butrylchoinesterase polymporphism = prolonged NM blockade

9

MOA - nondepolarizing blockers

competitive antagonists = overcome with inc acetylcholine (via AchE-I)

10

MOA - depolarizing blockers

activates nicotinic receptor depolarizes junction

causes fasiculations

not metabolizes by AchE

--> flaccid paralysis

rapid onset - short duration

11

NM blockers

all contain quarternary groups = doesn't cross BBB

inactive if given PO

12

half life vs kidney/liver excretion

kidney = longer t 1/2
liver = shorter t 1/2

13

benzylisoquinolones AE

hypotension d/t histamine release and slight ganglionic blockade (only with tubocurarine)

no effect on M2 receptors

14

ammonio steroids AE

produce tachycardia d/t blockade of muscarinic receptors == arrhythmias

no ganglion blockade

15

tubocurarine AE

ganglion blockade = hypotension and tachycardia

release histamine

16

succinylcholine AE

activates all autonomic cholinoreceptors

nicotinic = muscle pain
muscarinic = bradycardia

histamine release

d/t contractions at beginning:
hyperkalemia
increased intraocular pressure
inc intragastric pressure

malignant hyperthermia

NO CNS effects = no BBB penetration

17

drugs that enhance NM blockade

inhaled anesthetics
aminoglycosides
tetracyclines

18

aging and disease vs drug response to NM blockers

MG = inc NM blockade

adv age = prolongs blockade

severe burns and UMN dz = resistant to nondepolarizing relaxants

19

depolarizing blockers contraindications

hx malignant hyperthermia or myopathies

burns

trauma

denervation of skeletal muscle

UMN injury

20

reverse nondepolarizing NM blockade

AchE-I

atropine and glycopyrrolate are given to prevent bradycaria

21

spasmolytic drugs categories:

1) for chronic spasm
a: act in CNS
b: act directly on muscle

2) acute spasm

22

drugs that act in CNS as tx for chronic spasms

diazepam: agonist at GABA(a)

baclofen: agonist at GABA(b)

tizanidine: alpha2 agonist in CNS

23

baclofen

agonist at GABA(b)

used for chronic spasms tx

24

tizanidine

alpha2 agonist in CNS

used for chronic spamsms

25

botulinum toxin

act on skeletal muscle

for spastic disorders/cerebral palsy

26

drugs for acute spasm

centrally acting

relief of acute muscle spasm by trauma

cyclobenzaprine = prototype

AE: antimuscarinic side effects