Neuromuscular relaxants Flashcards
What are the two types of neuromuscular relaxants?
Non-depolarizing and depolarizing neuromuscular blockers
Describe the mechanism of depolarizing neuromuscular relaxants.
Will bind to the acetylcholine receptor and act as if it were ACh, causing depolarization of the post-synaptic cell. However, after this, it will not dissociate, disallowing further signal propagation or depolarization and resulting in flaccid paralysis.
Describe the mechanism of non-depolarizing neuromuscular relaxants.
ACh antagonist.
What is unique about curare-type drugs and their efficacy?
It usually is shorter in duration than the half-life by quite a bit, as there is a very high, narrow therapeutic range
Which of the two types of neuromuscular blockers works more quickly?
Depolarizing drugs
How are depolarizing drugs’ actions terminated?
By diffusing away from the receptor; they do not have AChE in the synapse.
How can the half-lives of depolarizing drugs be altered?
With AChE variants
What enzyme degrades both types of drugs?
Plasma cholinesterase
What are extra side effects caused by depolarizing agents?
Arrhythmias Hypertension Bradycardia Hyperkalemia Malignant hyperthermia
What is the antidote for either class of neuromuscular blockers?
Neostigmine
Glycopyrrolate in non-depolarizing
Atropine in phase I depolarizing block
What drug should be given to a patient with kidney failure?
Mivacurium
What drug should be given during long procedures?
Vecuronium/pancuronium
How does baclofen alter somatic motor neuron excitation?
It is a GABA agonist, so it reduces calcium influx and reduces release of excitatory transmitters in the spinal cord.
How do benzodiazepines alter somatic motor excitation?
Facilitate GABA-mediated presynaptic inhibition
What does GABA do?
Reduces activity of Ia fibers that excite the primary motor neuron and enhances activity of internuncial inhibitory neurons
