Antidysrhythmics Ia Norpace Flashcards
action of antidysrhythmic drugs
depress contractility, excitability and automaticity; block adrenergic (sympathetic) simulation; incrase repolarization (phase to move to refractory/rest phase)
define action potential
when there is movement of Na and K across cell membrane that causes depolarization/contraction
define refractory phase
resting state; phase 4 of action potential; cell CANNOT respond to new stimulus; K is inside and Na is outside once again
define automaticity
electrical impulse formation
define excitability or irritability
cell CAN respond to stimulus
define depolarization
muscle activated; contraction starts; systole to eject blood; Na rushing inside and Ca joined in, while K moving outside; phase starts at 0
define repolarization
movement towards refractory/resting phase; K is completely out now; phase starts at 1 and plateaus at phase 2 and continues to phase 3 of action potential
the phase between repolarization and refractory phase?
phase 3; magnesium activates the Na-K pump to fascilitate the movement of K back into the cell; Na and Ca move out; when complete, refractory phase 4 has been reached.
define refractory phase
resting state; diastole to fill in with blood; phase 4 of action potential; cell CANNOT respond to new stimulus; K is inside and Na is outside once again
Sodium channel blockers does this
decrease fast influx of Na into cell; depress past 0 of action potential; effect is decrease automaticity/formation and conduction of electrical stimulus
indication of sodiume channel blockers
tx L/T dysrhythmias
contraindications of sodium channel blockers
cardiogenic SHOCK; 2nd or 3rd AV BLOCK; GLAUCOMA; caution cardiomyopathy, renal, hepatic d/o
nsg responsibilities with sodium channel blockers
PC HF, hypokalemia, hypernatremia (?)
sodium channel blockers are divided into 3 subgroups
Ia, Ib, Ic
sodium channel blocker Subclass Ia does this
slow conduction and prolong repolarization
example of subclass Ia drug
Norpace
Sublcass Ia Norpace indication
Vetricular Tachycardia and Premature Ventricular Contractions; remember Ia slows conduction and prolong repolarization; you’re that much further away from having another depolarization
subclass Ia Norpace a/e
precipitate CHF (r/t decreased heart pump) and hypotension
subclass Ia Norpace contraindication
cardiogenic SHOCK; 2nd or 3rd AV BLOCK; GLAUCOMA; caution cardiomyopathy, renal, hepatic d/o
subclass Ia Norpace is a BBW, so use it on pts that are
at risk of dying anyway; got nothing to lose at this point
with subclass Ia Norpace, if pt is dizzy check what?
HR and BP
