heart failure drugs Flashcards
digoxin mechanism
inhibits the Na/K ATPase resulting in more sodium and consequently more Ca in the cell. this increases the actin-myosin interaction and allows for greater force of contraction.
what is the secondary mechanism for digoxin
it also causes increased neuronal stimulation of the vagas nerve and thus increased PANS stimulation resulting in decreased HR. the decreased HR causes more filling time and more efficient pumping
how is digoxin cleared from the body?
renal excretion. must take caution in renal impairment
uses of digoxin
SVT, and CHF.
what do we never use digoxin for
WPW
what are the early SE of digoxin
anorexia, nausea, ECG changes
what are the later SE of digoxin
disorientation, visual effects such as halos. cardiac toxicity
what to use if cardiotoxic digoxin
digibind
what is required when using digoxin
a loading dose is required. this is digitalization
what does digoxin interact with
diuretics due to electrolyte abnormalities. quinidine and verapamil due to displacement and tissue binding.
what is the mechanism for inamrinone and milranone
increases cAMP in the heart resulting in increased inotropy. the increase in cAMP in SM leads to a decrease in the TPR.
what is the mechanism of dobutatmine and dopamine
sympathomimetics -direct beta 1 agonists. increase the contraction
what is the problem with direct beta 1 agonists for CHF
they desensitize rapidly.
what is nesiritide
recombinant b-type naturetic peptide. used in acutely decompensated CHF
what beta blockers do we use in CHF
ones that have intrinsic sympathomimetic activity
