Skele Muscle Relaxants Flashcards
The antagonistic nondeplolarizing neuromuscular muscle relaxants are divided into two categories. Name the 4 drugs in the Benzylisoquinolines
Tubocurarine (prototype)
Atracurium
Cisatracurium
Mivacurium
-curium
What are the two broad categories of skeletal muscle relaxants? Each of their two major subcategories?
Neuromuscular blockers: antagonists(nondepolarizing) and agonists (depolarizing)
Spasmolytics: chronic spasm and acute spasm
The antagonistic nondeplolarizing neuromuscular muscle relaxants are divided into two categories. Name the 3 drugs in the ammonio steroids
Pancuronium
Rocuronium
Vecuronium
-uroniums
Name the only depolarizing neuromuscular blocker muscular relaxant
Succinylcholine
Which two drugs can be used to overcome the competitive neuromuscular block caused by nondeplolarizing muscular relaxants?
Neostigmine and edrophonium
AchE inhibitors
Which muscle relaxant first causes fascications before eventually resulting in flaccid paralysis?
Succinylcholine (depolarizing - lots of activation first, then no more neurotransmitter)
What is the preferred method of delivery for neuromuscular blockers? Why?
IV or IM
Highly polar and poorly lipid soluble (don’t cross membranes - inactive if given orally)
What is the only short acting neuromuscular blocker muscle relaxant?
Mivacurium
Name the two long acting neuromuscular blocking muscular relaxants
Tubocurarine
Pancuronium
How does renal excretion compare to hepatic excretion in terms of half life and duration of action?
Drugs excreted by liver typically have shorter half lives and shorter durations of action (think first pass metabolism). Kidney excreted drugs have longer half lives and durations of action
Which nondepolarizing neuromuscular muscle relaxant is good for use in patients with hepatic or renal failure? Why?
Atracurium/Cisatracurium
They are eliminated spontaneously and don’t require metabolism by kidney/liver
After treatment with a nondepolarizing neuromuscular blocking muscle relaxant, patient experiences hypotension and seizures. What drug is responsible? What is an alternative treatment?
Atracurium has a metabolite that is responsible (laudsnosine)
Cisatracurium has less side effects
Which is the nondepolarizing neuromuscular blocking muscle relaxant has the most rapid onset and is a good alternative to succinylcholine for rapid intubation?
Rocuronium
Patient after a procedure required mechanical ventilation due to a rare defect in their butyrylcholinesterase enzyme. What two muscle relaxants could be responsible for this?
Succinylcholine and mivacurium
Both degraded by butyrylcholinesterase
Name the major side affect of the benzylisoquinolines and ammonio steroids (subgroups of nondepolarizing neuromuscular blocking muscle relaxants)
Benzy: hypotension and histamine release
Tubocurarine(worst), mivacurium, and Atracurium
Ammonio: arrhythmia due to muscarinic blockade
After a procedure a patient complains of muscle pain. What neuromuscular blocking muscle relaxant did he probably receive?
Succinylcholine - depolarizing so fasciculations first - contraction can cause pain
Which muscle relaxant is contraindicated in burn patients? Due to what side effect?
Succinylcholine
Hyperkalemia (worsened in burn patients and released during depolarization)
Which muscle relaxant can increase intraocular and intragastric pressures?
Succinylcholine
Treatment for malignant hyperthermia?
Dantrolene
Which muscle relaxatant has effects at both the Nn and Nm receptors?
Succinylcholine
Which two muscle relaxants can cause hypotension through histamine release?
Tubocurarine and mivacurium
Slight effects by Atracurium and succinylcholine
Which three classes of drugs must be used with caution when giving neuromuscular blocking muscle relaxants due to their ability to enhance the blockade?
Inhaled anesthetics
Aminoglycosides
Tetracyclines
In terms of the neuromuscular blockade, give two conditions that can increase it, and two conditions that are resistant to it
Increase: myasthenia gravis and advanced age (dec drug clearance)
Resistant: burn patients and upper motor neuron disease (due to proliferation of extrajunctional receptors)
What drug can be used to prevent the bradycardia that follows a procedure using a neuromuscular blocker?
Glycopyrrolate (muscarinic antagonist) - usually comes in same vial as edrophonium which reverses the blockade
Which spasmolytic is an agonist of GABAa receptors in the CNS?
Diazepam
Which spasmolytic is an agonist at GABAb receptors in the CNS?
Baclofen
Which spasmolytic is an alpha 2 agonist is CNS?
Tizanidine
Which spasmolytic increases GABA release in the CNS?
Gabapentin
Saw this one in epilepsy and neuropathic pain treatments
Which spasmolytic is an agonist of both GABAa and GABAb in the CNS?
Progabide
Name a non-GABA inhibitory neurotransmitter in the CNS that can be used as a spasmolytic
Glycine
Name two spasmolytics that are new drugs for the treatment of ALS
Idrocilamide and riluzole
Name the three spasmolytics that act directly on the skele muscle as opposed to having central effects
Dantrolene
Botulinum toxin
Cyclobenzaprine
Which spasmolytic can be used in the treatment of cerebral palsy?
Botulinum toxin
Which spasmolytic is used for the relief of acute muscle spasm caused by local trauma or strain and can cause sedation and sometimes transient visual hallucinations?
Cyclobenzaprine
