HF4 Flashcards
(30 cards)
what effect does hyperkalemia have on digoxin?
what effect does hypokalemia have
hyperkalemia = less benefits of digoxin hypokalemia = digoxin toxicity
what are the adverse effects of digoxin
muscle weakness agitation vision problems fatigue anorexia nausea and vomiting
what should be used for digoxin toxicity treatment
digoxin immune fab (digibind)
what category is amiodarone’s interaction with digoxin?
what should be done if taken together
category D
decrease digoxin dose by 1/3 to 1/2
what is the interaction category of verapamil and digoxin?
what should be done if taken together
category C monitor closely (can increase digoxin conc.)
what category interaction is spironolactone and digoxin?
what should be done if taken together
category C monitor closely (can increase digoxin conc.)
what category interaction is quinidine and digoxin?
what should be done if taken together
category D
decrease digoxin dose by 1/4 to 1/2
what is the MOA of beta agonists in HF (3 steps)?
- activates adenylyl cyclase which produces cAMP
- cAMP activates protein kinase
- phosphorylation of L type Ca channel increases Ca conc.
what are two B agonists for HF
Dopamine
Dobutamine
what is increased by B agonists
increases:
inotropic = FOC
chronotropic = HR
lusitropic = relaxation rate
what beta adrenergic agonist is used for short term treatment of severe, refractory chronic HF
Dopamine
why is dopamine only used short term?
increase in oxygen demand due to tachycardia
what are the adverse effects of dopamine
tachycardia
arrhythmias
what do low doses of dopamine do
cause vasodilation in periphery by binding to receptors on KIDNEYS
also causes diuresis
what do intermediate doses of dopamine do?
cause vasodilation via B2 receptors and increase HR and FOC via B1 receptors
what do high doses of dopamine do
cause vasoconstriction throughout body via alpha1 receptors
what does high doses of dopamine do to hemodynamics
increase afterload and SVR
what receptor is effected the most by both enantiomers of dobutamine
beta1 effected most
what enantiomer of dobutamine is an alpha1 antagonist
+ enantiomer
what enantiomer of dobutamine is an alpha1 agonist
- enantiomer
what are the hemodynamic effects of dobutamine
increase SV and increase CO
what are some adverse effects of dobutamine
angina
tachycardia
why do b-agonists development create tolerance
receptor down regulation
what is the MOA of phosphodiesterase inhibitors in HF?
inhibit breakdown of cAMP, causing phosphorylation of L-type Ca channel, increasing Ca conc
