Muscle Relaxants Flashcards
What are the two groups of skeletal muscle relaxants?
1) Muscle Paralyzers AKA neuromuscular blocking agents or neuromuscular blockers
2) Spasmolytics- reduce muscle spasm
When are neuromuscular blocking agents (muscle paralyzers) used?
- when we want muscle paralysis
- surgery or in ICU on ventilator
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)
Do neuromuscular blocking agents have an effect of the brain?
NO. The patient is aware they can’t move if they are awake
Route of administration for neuromuscular blocking agents
IV
Can neuromusclar blocking agens get into the CNS
no they are polar
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
List the Nondepolarizing Neuromuscular Blockers
- Curare- first discovered, darts
- curium
pancuronium- long acting
MOA of nondepolarizing blockers
competitive antagonists to acetylcholine (nicotinic subtype) receptor at the neuromuscular junction but does not activate receptor
How do you reverse nondepolarizing blockers?
acetycholine esterase- floods synapse with acetylcholine
What is the progression of paralysis with nondepolarizing neuromuscular blockers?
motor weakness - skeltal muscles flacid- larger muscles paralyzed last - diaphragm very last
What is the only depolarizing neuromuscular blocker? how long does it last?
succinycholine
SHORT 5-10 minutes
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
CVS effects of depolarizing neuromuscular blockers are
1) hypotension from histamine release
2) arythmias
what can you give to prevent hypotension with depolarizing neuromuscular blockers?
anti histamines
What patient dispositions leads to hyperkalemia in they are given depolarizing neuromuscular blockers?
-burns
-nerve damage
-neuromuscular dz
trauma