Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
30 Cards in this Set
- Front
- Back
Depolarizing Agent
|
binds to nicotinic receptors at NMJ
causes initial depolarization & muscle contraction |
|
Phase I --depolarizing agent
|
occupies receptor longer than ACh, prevention repolarization and further depolarization
|
|
Phase II -- depolarizing agent
|
with time, membrane gradually repolarizes, but is desensitized since nicotinic receptors are still occupied
|
|
Phase I vs. Phase II --Depol. agen
|
Phase I = flaccid paralysis = can't reverse block
Phase II = neostigmine may reverse block |
|
Succinylcholine
|
is a depolarizing drug
|
|
Competitive "non-depolarizing" Drugs
|
d-tubocurarine
pancuronium atracurium vercuronium rocuronium mivacurium --- not in U.S. |
|
Competitive Agents
|
bind to nicotinic receptors @ NMJ
block in competitive manner = flaccid paralysis "Limp" small muscles 1st > large later > diaphragm last |
|
Malignant Hyperthermia
|
fast rise in body temperature + muscle contractions
due to excessive Calcium release in a genetically susceptible patient assoc. w/ genetic mutation of autosomal dominant mutation chromosome 19 |
|
Succinylcholine -- adverse effect
|
malignant hyperthermia
due to excessive Calcium release in a genetically susceptible |
|
Malignant Hyperthermia-- drug reactions
|
anesthetics -- malignant hyperthermia
anti-psychotics -- neuroleptic malignant syndrome |
|
Duration of Action -- depolarizing v. competitive
|
Depolarizing agent = quick start, short duration
Competitive agent = slower start, longer duration |
|
Duration of Action -- specific drug
|
Succinylcholine = 1 min start, 5 min duration
Pancuronium = 1.5 min start, 3 hour duration Atracurium = 1.5 min start, 30 min duration |
|
Baclofen
|
GABAa agonist
↑K+ conductance in Spinal Cord neurons = decrease Excitatory Neurotransmitter release |
|
Baclofen -- clinical use
|
multiple sclerosis (MS) and other spasticity disorders
|
|
Diazepam
|
binds to benzodiazepine site on GABAa receptor
↑chloride influx in response to stimulation of receptor = ↑↑ GABA mediated inhibition |
|
Diazepam -- clinical uses
|
decrease muscle tone in muscle spasms of any cause
|
|
Dantrolene
|
prevents calcium release from sarcoplasmic reticulum in skeletal muscle
|
|
Dantrolene -- clinical use
|
prevents Excessive Ca release in genetically susceptible patients
Prevents adverse effects ..... Malignant Hyperthermia (succinylcholine ) Neuroleptic Malignant syndrome (anti-psychotics) |
|
Cyclobenzaprine & Carisoprodol
|
treat acute local muscle spasm
believe to act thru brainstem to relieve muscle spasm to acute muscle injury |
|
Depolarizing and Competitive Muscle Relaxants
|
treat muscle paralysis during . . .
Surgery Mechanical Ventilation (w/ anesthetic agent) |
|
Succinylcholine -- Adverse Effects
|
Excessive intracellular Calcium = malg. hyperthermia
Hyperkalemia = patients w/ damaged skeletal muscle |
|
Pancuronium -- Adverse Effect
|
Cardiac Muscarinic block
|
|
Curare---Adverse Effects
|
Histamine release
Ganglionic Block |
|
Atrcurium -- Adverse Effect
|
Histamine release
|
|
What drugs trigger histamine release?
|
Curare (d-turbocararine)
Atracurium |
|
What triggers Ganglionic Block?
|
Curare -- competive nondepolarizing msk relaxant
|
|
Prolongs duration of Succinylcholine effects
|
genetic defect leading to deficient cholinesterases
|
|
Succinylcholine -- metabolism
|
rapidly metabolized by plasma cholinesterases
|
|
What drug's effects can be reversed by cholinesterase inhibitors?
|
Succinylcholine
(-) cholinesterase = (-) metabolic breakdown |
|
Neostigmine
|
reversible acetylcholinesterase inhibitor
(-) ACh metabolism = more ACh = stimulates muscle reverses Succinylcholine muscle relaxation |